diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index f6007f02c..113ffec8e 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -15,7 +15,7 @@ env:
   # renovate: datasource=npm depName=npm
   NPM_VERSION: "11"
   # renovate: datasource=npm depName=@microbit-foundation/python-editor-v3-microbit registryUrl=https://npm.pkg.github.com
-  THEME_VERSION: 0.3.0
+  THEME_VERSION: 0.3.0-analytics.ga4.98
   # renovate: datasource=npm depName=@microbit-foundation/website-deploy-aws registryUrl=https://npm.pkg.github.com
   DEPLOY_AWS_VERSION: "0.6.0"
   # renovate: datasource=npm depName=@microbit-foundation/website-deploy-aws-config registryUrl=https://npm.pkg.github.com
diff --git a/AGENTS.md b/AGENTS.md
index 45578fc37..a3cd593f3 100644
--- a/AGENTS.md
+++ b/AGENTS.md
@@ -19,6 +19,15 @@ its own copies of React and friends, so leave it in place either way.
 After bumping the pinned `@microbit/ui` version, follow "Upgrading in an app" in
 `../ui/packages/ui/README.md`.
 
+## Analytics
+
+Events go through `Logging` (`src/logging/`) and are documented in
+`docs/analytics-events.md`; update the doc when adding or changing an event.
+Names are snake_case with flat primitive params. gtag only exists on
+Foundation builds (`VITE_FOUNDATION_BUILD`, see `index.html`), so OSS and
+local dev log events to the console instead. The private theme package
+supplies brand config only, including the `product` analytics slug.
+
 ## Commands
 
 - Unit tests: `npm test` (vitest). E2e: run headlessly via
diff --git a/docs/analytics-events.md b/docs/analytics-events.md
new file mode 100644
index 000000000..06f9a4b2f
--- /dev/null
+++ b/docs/analytics-events.md
@@ -0,0 +1,299 @@
+# Analytics events
+
+Analytics events emitted by the app. The catalogue is aligned with
+ml-trainer's `docs/analytics-events.md` so the two apps can share GA4 custom
+definitions where the concept matches; the "Removed / migrated events" table
+at the end maps the previous UA-shaped events to their replacements.
+
+## Overview
+
+- The web build emits via gtag. GA4 Enhanced Measurement auto-collects
+  `page_view` (including `pushState` navigation between documentation pages),
+  `session_start`, `first_visit`, `user_engagement`, etc. Those are not
+  redocumented here.
+- gtag is only present when `shared-assets/common.js` is loaded, which
+  `index.html` does only for Foundation builds (`VITE_FOUNDATION_BUILD`), and
+  the script itself is hostname-gated to `*.microbit.org`. Consent is owned by
+  the shared-assets cookie modal, which only offers the GA opt-in on
+  PRODUCTION / STAGING. OSS forks and local dev therefore send nothing: events
+  fall through to the console via the Sentry-breadcrumb fallback.
+- Backend code: `src/logging/logger.ts` (param building, Sentry, product
+  injection) and `src/logging/sink.ts` (gtag). Shared device-event
+  vocabulary and helpers are in `src/logging/analytics.ts`.
+- Names are snake_case, ≤40 chars. Param values are primitives (string
+  ≤100 chars, number, or boolean). These are Firebase's rules; the editor has
+  no native build today but the catalogue is kept compatible so a future one
+  could share it.
+- Every event automatically carries a **`product`** param (`python-editor`),
+  injected by the logger from `BrandConfig.product`. It's not listed on
+  individual event tables. Lets dashboards split traffic by product when
+  sibling apps share a GA4 property.
+- Numeric params (`files`, `lines`, `storage_used`, `errors`, `modules`,
+  `duration_ms`, `count`) are sent raw and should be registered as GA4 **custom
+  metrics**, not dimensions. The UA-era bucketing (`0-5`, `51-100`, …) is gone;
+  bucket in the reporting layer if needed.
+- Param names are deliberately generic so one GA4 custom definition serves
+  both apps: `surface` is "which part of the UI" (ml-trainer: home / projects
+  / toolbar; here: the sidebar tab), `id` is "the content item this event is
+  about" (the event name says what kind), `state` is the resulting state of a
+  toggle, `count` is "how many things this event touched", `is_default` is
+  "still the unedited starter". Prefer reusing one of these over adding a
+  product-specific name.
+
+## User properties
+
+Set once on app boot. Auto-attach to every subsequent event for the same user,
+available as user-scoped breakdowns in GA4.
+
+| Name               | Values       | Set when | Notes                                                          |
+| ------------------ | ------------ | -------- | -------------------------------------------------------------- |
+| `webusb_available` | `yes` / `no` | App boot | From `"usb" in navigator`. Same name and values as ml-trainer. |
+
+Unlike ml-trainer there is no `webbluetooth_available`: the editor doesn't use
+Bluetooth.
+
+## Device events
+
+Same event family and params as ml-trainer so a cross-product device dashboard
+works with one set of custom definitions. The editor has no connection state
+machine, so the step set is small and there are no `from` / `via` params.
+
+Every `device_*` event carries:
+
+- **`task`** — `connect` (the user pressed Connect, or a flash needed a
+  connection first) or `download` (the user pressed Send to micro:bit and a
+  flash was attempted). `connect` is deliberately not ml-trainer's
+  `data_connection`: there it means live sensor data for recording, here it
+  means serial / REPL plus fast flashing.
+- **`transport`** — always `web_usb`. A new value alongside ml-trainer's
+  `web_bluetooth` / `native_bluetooth` / `radio`; describes the user's setup,
+  consistent with how ml-trainer uses it on `download` events.
+
+Browsers without WebUSB can't use the connect flow at all. We emit no
+`device_*` events for that cohort; the `webusb_available` user property
+captures the segment.
+
+### `device_step`
+
+| Param       | Values                                                                                                                              |
+| ----------- | ----------------------------------------------------------------------------------------------------------------------------------- |
+| `task`      | `connect` / `download`                                                                                                              |
+| `step`      | `connect_help` (the connect help dialog was shown), `connecting` (WebUSB chooser / connect in progress), `flashing` (flash started) |
+| `transport` | `web_usb`                                                                                                                           |
+
+### `device_success`
+
+| Param          | Values                                                                                                          |
+| -------------- | --------------------------------------------------------------------------------------------------------------- |
+| `task`         | `connect` / `download`                                                                                          |
+| `transport`    | `web_usb`                                                                                                       |
+| `duration_ms`  | int — wall-clock flash time (download task only). Revives the dead `WebUSB-time` event as a raw metric.         |
+| `files`        | int — files in the project (download task only)                                                                 |
+| `lines`        | int — line count of `main.py` (download task only)                                                              |
+| `is_default`   | boolean — `main.py` is still the unedited starter program (download task only)                                  |
+| `storage_used` | int — bytes of micro:bit filesystem used (download task only)                                                   |
+| `errors`       | int — diagnostics the language server currently reports (download task only)                                    |
+| `modules`      | int — files carrying our module metadata header, i.e. modules added from Reference / Ideas (download task only) |
+
+The project stats params are the same set as `project_save`, so "what does a
+typical program look like when it reaches a micro:bit" is one query.
+
+### `device_failure`
+
+| Param       | Values                                                                                                                                                                                                                |
+| ----------- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
+| `task`      | `connect` / `download`                                                                                                                                                                                                |
+| `at_step`   | `connecting` / `flashing`                                                                                                                                                                                             |
+| `code`      | `DeviceError` code: `no-device-selected`, `device-disconnected`, `firmware-update-required`, `device-in-use`, `timeout`, `connection-error`, `unsupported`; `flash-data` for a hex build failure; `unknown` otherwise |
+| `transport` | `web_usb`                                                                                                                                                                                                             |
+
+### `device_exit`
+
+User pressed Cancel on the connect help dialog.
+
+| Param       | Values                 |
+| ----------- | ---------------------- |
+| `task`      | `connect` / `download` |
+| `at_step`   | `connect_help`         |
+| `reason`    | `close`                |
+| `transport` | `web_usb`              |
+
+### `device_disconnect`
+
+| Param       | Values                                                                                                                        |
+| ----------- | ----------------------------------------------------------------------------------------------------------------------------- |
+| `reason`    | `user` (Disconnect button) / `unknown` (status went from connected to disconnected or unauthorised otherwise, e.g. unplugged) |
+| `transport` | `web_usb`                                                                                                                     |
+
+## Project events
+
+### `project_save`
+
+User saved from the project Save menu. Both variants prompt for a project name
+first.
+
+| Param                                                               | Values                                                                                       |
+| ------------------------------------------------------------------- | -------------------------------------------------------------------------------------------- |
+| `format`                                                            | `hex` (Save hex: whole project plus MicroPython) / `py` (Save Python script: `main.py` only) |
+| `files`, `lines`, `is_default`, `storage_used`, `errors`, `modules` | As on `device_success`.                                                                      |
+
+No `destination` param: the editor only downloads. ml-trainer's
+`destination: download | share` distinguishes its native share sheet.
+
+### `project_import`
+
+User brought files in. Fires once per drop / picker selection, before the
+files are parsed, so it counts attempts.
+
+| Param    | Values                                                                                                                                     |
+| -------- | ------------------------------------------------------------------------------------------------------------------------------------------ |
+| `source` | `drop` / `file_picker` (same values as ml-trainer)                                                                                         |
+| `format` | `hex` (replaces the project) / `py` (Python file added to the project) / `other` (any other single file) / `multiple` (more than one file) |
+
+### `project_reset`
+
+User chose Reset project, replacing everything with the starter program. Fires
+when the menu action is chosen, before the confirm dialog. No params.
+
+### `project_rename`
+
+User set the project name, from the header or the name-your-project prompt on
+save. No params.
+
+### `idea_open`
+
+User opened an idea into the editor.
+
+| Param | Values                     |
+| ----- | -------------------------- |
+| `id`  | The idea slug, e.g. `dice` |
+
+## File events
+
+Per-file actions from the Project (files) area.
+
+| Event         | Params | When fired                                              |
+| ------------- | ------ | ------------------------------------------------------- |
+| `file_create` | —      | User created a new file                                 |
+| `file_delete` | —      | User chose delete on a file (before the confirm dialog) |
+| `file_save`   | —      | User downloaded a single file from the files list       |
+
+## Documentation events
+
+The Reference / Ideas / API sidebar. Page views for each documentation page are
+already auto-collected via `page_view` because navigation uses `pushState`;
+these events add the _how_.
+
+### `docs_navigate`
+
+Fires on programmatic navigation into a documentation page. Browser
+back/forward and typed URLs don't fire it (they are `page_view` only).
+
+| Param     | Values                                                                                                                                     |
+| --------- | ------------------------------------------------------------------------------------------------------------------------------------------ |
+| `via`     | `user` (clicked in the sidebar), `search` (picked a search result), `code` (from a code hover/help link), `simulator` (from the simulator) |
+| `surface` | `reference` / `ideas` / `api`                                                                                                              |
+| `id`      | The page slug, e.g. `buttons`; absent when navigating to a tab root                                                                        |
+
+### `docs_search`
+
+Fires once per search session: when results first appear after typing, not
+per keystroke (300ms debounce) and not again until results are cleared. No
+params. Search terms are deliberately not sent.
+
+## Code snippet events
+
+Moving code from the documentation into the editor. Drag and copy are the
+starts; drop and paste are the completions, so drop ÷ drag is the drag-and-drop
+success rate.
+
+| Event        | Params          | When fired                                                                  |
+| ------------ | --------------- | --------------------------------------------------------------------------- |
+| `code_drag`  | `surface`, `id` | User started dragging a snippet from the sidebar                            |
+| `code_drop`  | `surface`, `id` | The snippet landed in the editor                                            |
+| `code_copy`  | `surface`, `id` | User used the snippet's copy button                                         |
+| `code_paste` | `surface`, `id` | A copied snippet was pasted into the editor (via our own clipboard context) |
+
+- `surface` — `reference` / `ideas` / `api`.
+- `id` — the documentation slug for Reference / Ideas, or the fully qualified
+  name for API (e.g. `microbit.display.scroll`). Bounded cardinality, but
+  large; expect `(other)` in standard reports and use Explorations.
+
+## Editor events
+
+The CodeMirror code editor.
+
+| Event                 | Params                 | When fired                                                                                |
+| --------------------- | ---------------------- | ----------------------------------------------------------------------------------------- |
+| `editor_paste`        | `count:int`            | Text pasted from outside the app (not a snippet paste). `count` is the pasted line count. |
+| `editor_undo`         | —                      | Undo via the toolbar (keyboard undo is not tracked)                                       |
+| `editor_redo`         | —                      | Redo via the toolbar                                                                      |
+| `editor_zoom`         | `direction: in \| out` | Font size changed via the zoom buttons                                                    |
+| `editor_autocomplete` | —                      | User accepted an autocomplete suggestion                                                  |
+
+## Serial events
+
+The serial / REPL panel.
+
+| Event              | Params                      | When fired                                                                            |
+| ------------------ | --------------------------- | ------------------------------------------------------------------------------------- |
+| `serial_toggle`    | `state: expand \| collapse` | User expanded or collapsed the serial area                                            |
+| `serial_help`      | —                           | User opened the serial hints and tips                                                 |
+| `serial_interrupt` | —                           | User sent Ctrl-C                                                                      |
+| `serial_reset`     | —                           | User sent Ctrl-D                                                                      |
+| `serial_traceback` | —                           | A MicroPython traceback arrived from the device (first one per run; cleared on reset) |
+
+## Simulator events
+
+| Event          | Params                  | When fired                                                                                                                                                                                                                                      |
+| -------------- | ----------------------- | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
+| `sim_start`    | —                       | User ran the program in the simulator                                                                                                                                                                                                           |
+| `sim_stop`     | —                       | User pressed stop (stops caused by code changes are not counted)                                                                                                                                                                                |
+| `sim_reset`    | —                       | User pressed reset                                                                                                                                                                                                                              |
+| `sim_audio`    | `state: mute \| unmute` | User toggled simulator sound                                                                                                                                                                                                                    |
+| `sim_sensor`   | `id`                    | First time in the session the user changed a given input, e.g. `accelerometerX`, `gesture`, `compassHeading`, `pin0`, `pinLogo`, `temperature`, `lightLevel`, `soundLevel`, `buttonA`, `buttonB`, `radio_input`. Once per sensor per page load. |
+| `sim_log_save` | —                       | User downloaded the simulated data log as CSV                                                                                                                                                                                                   |
+
+## Layout events
+
+| Event            | Params                 | When fired                             |
+| ---------------- | ---------------------- | -------------------------------------- |
+| `sidebar_toggle` | `state: open \| close` | User collapsed or expanded the sidebar |
+
+## Removed / migrated events
+
+Migration notes from the previous UA-shaped events. Every old event was sent
+with `event_category: "Python Editor V3"`, the message as `event_label`, and
+`value` (default 1); none of that survives. Listed for grep-ability when
+reading old dashboards.
+
+| Old name                                                                                           | Status                                                                                                                                |
+| -------------------------------------------------------------------------------------------------- | ------------------------------------------------------------------------------------------------------------------------------------- |
+| `boot` → `WebUSB-available`                                                                        | Dropped. Replaced by the `webusb_available` user property. `session_start` auto-fires.                                                |
+| `connect`                                                                                          | Replaced by `device_step` (`task: connect`) and `device_success` / `device_failure` / `device_exit`.                                  |
+| `disconnect`                                                                                       | Renamed `device_disconnect`; widened with `reason` to also capture unexpected drops.                                                  |
+| `flash` (+ fan-outs `files`, `fs-used`, `lines`, `lines-value`, `code-errors`, `magic-modules`)    | Replaced by `device_step` (`step: flashing`) and `device_success` (`task: download`) with raw numeric params.                         |
+| `save` (+ the same fan-outs)                                                                       | Renamed `project_save` with `format: hex` and raw numeric params.                                                                     |
+| `save-main-file`                                                                                   | Folded into `project_save` with `format: py`.                                                                                         |
+| `save-file`                                                                                        | Renamed `file_save`.                                                                                                                  |
+| `create-file` / `delete-file`                                                                      | Renamed `file_create` / `file_delete`.                                                                                                |
+| `set-project-name`                                                                                 | Renamed `project_rename`.                                                                                                             |
+| `reset-project`                                                                                    | Renamed `project_reset`.                                                                                                              |
+| `idea-open`                                                                                        | Renamed `idea_open`; slug moved from label to the `id` param.                                                                         |
+| `drop-load` / `file-upload` → `load` with label `<type>-<ext>`                                     | Consolidated to `project_import` with `source` and `format` params.                                                                   |
+| `documentation-user` / `-search` / `-from-code` / `-from-simulator` with label `tab-slug`          | Consolidated to `docs_navigate` with `via`, `surface`, `id` params.                                                                   |
+| `search`                                                                                           | Renamed `docs_search`.                                                                                                                |
+| `code-drag` / `code-drop` / `code-copy` / `code-paste` with label `<toolkit>-<slug>` or `api-<id>` | Same names in snake_case; label split into `surface` and `id` params.                                                                 |
+| `paste` (value = line count)                                                                       | Renamed `editor_paste`; line count moved to the `count` param.                                                                        |
+| `undo` / `redo`                                                                                    | Renamed `editor_undo` / `editor_redo`.                                                                                                |
+| `zoom-in` / `zoom-out`                                                                             | Consolidated to `editor_zoom` with `direction`.                                                                                       |
+| `autocomplete-accept`                                                                              | Renamed `editor_autocomplete`.                                                                                                        |
+| `sidebar-toggle` with label `open` / `close`                                                       | Renamed `sidebar_toggle`; label moved to the `state` param.                                                                           |
+| `serial-expand` / `serial-collapse`                                                                | Consolidated to `serial_toggle` with `state`.                                                                                         |
+| `serial-info`                                                                                      | Renamed `serial_help`.                                                                                                                |
+| `serial-interrupt` / `serial-reset` / `serial-traceback`                                           | Same names in snake_case.                                                                                                             |
+| `sim-user-start` / `sim-user-stopped` / `sim-user-reset`                                           | Renamed `sim_start` / `sim_stop` / `sim_reset`.                                                                                       |
+| `sim-user-mute` / `sim-user-unmute`                                                                | Consolidated to `sim_audio` with `state`.                                                                                             |
+| `sim-user-<sensorId>`                                                                              | Consolidated to `sim_sensor` with the `id` param.                                                                                     |
+| `sim-user-data-log-saved`                                                                          | Renamed `sim_log_save`.                                                                                                               |
+| `WebUSB-time`                                                                                      | Was already dead (the emitter went with the connection-library extraction in Feb 2025). Revived as `duration_ms` on `device_success`. |
diff --git a/package-lock.json b/package-lock.json
index 49301cde2..5838d2c41 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -21,6 +21,7 @@
         "@microbit/ui-patterns": "^0.4.0",
         "@sanity/block-content-to-react": "^3.0.0",
         "@sanity/image-url": "^1.0.1",
+        "@sentry/browser": "^10.71.0",
         "@testing-library/jest-dom": "^5.14.1",
         "@testing-library/react": "^14.0.0",
         "@testing-library/user-event": "^14.4.3",
@@ -4535,6 +4536,95 @@
         "node": ">=10.0.0"
       }
     },
+    "node_modules/@sentry/browser": {
+      "version": "10.71.0",
+      "resolved": "https://registry.npmjs.org/@sentry/browser/-/browser-10.71.0.tgz",
+      "integrity": "sha512-fTE9tUDoggJSFv8cQ+h1UA9onovOoUNJWu8Var1MXmUVuVG/W3WqzJFVyKArZMj95lizZkq8aiS63SURvrBsFQ==",
+      "license": "MIT",
+      "dependencies": {
+        "@sentry/browser-utils": "10.71.0",
+        "@sentry/conventions": "^0.16.0",
+        "@sentry/core": "10.71.0",
+        "@sentry/feedback": "10.71.0",
+        "@sentry/replay": "10.71.0",
+        "@sentry/replay-canvas": "10.71.0"
+      },
+      "engines": {
+        "node": ">=18"
+      }
+    },
+    "node_modules/@sentry/browser-utils": {
+      "version": "10.71.0",
+      "resolved": "https://registry.npmjs.org/@sentry/browser-utils/-/browser-utils-10.71.0.tgz",
+      "integrity": "sha512-Djhb+RdEwSdYTlDaMzc2uRCA+bYDIFsFCtZzKEtB9UR7lJNV/bJ0k3el3ifaVGTRELO8WBll/X0elty1Dk5tTw==",
+      "license": "MIT",
+      "dependencies": {
+        "@sentry/conventions": "^0.16.0",
+        "@sentry/core": "10.71.0"
+      },
+      "engines": {
+        "node": ">=18"
+      }
+    },
+    "node_modules/@sentry/conventions": {
+      "version": "0.16.0",
+      "resolved": "https://registry.npmjs.org/@sentry/conventions/-/conventions-0.16.0.tgz",
+      "integrity": "sha512-fO9PLmHdVURcSPUpWCItWAtgKiMwGdJHbovoSEyLplX5sxs2ugvI4CBPTrkkgqhObnZOD0CnWBKDzSVQYBKEyQ==",
+      "license": "MIT",
+      "engines": {
+        "node": ">=14"
+      }
+    },
+    "node_modules/@sentry/core": {
+      "version": "10.71.0",
+      "resolved": "https://registry.npmjs.org/@sentry/core/-/core-10.71.0.tgz",
+      "integrity": "sha512-OIjT7rzcWJjUC6r3eBT3Td1j0afDBMkbbx9jTocSD+ZSfc25eEU7hoIPS0WvfeIOTIN3y8bfQnXavwMReaNVHQ==",
+      "license": "MIT",
+      "dependencies": {
+        "@sentry/conventions": "^0.16.0"
+      },
+      "engines": {
+        "node": ">=18"
+      }
+    },
+    "node_modules/@sentry/feedback": {
+      "version": "10.71.0",
+      "resolved": "https://registry.npmjs.org/@sentry/feedback/-/feedback-10.71.0.tgz",
+      "integrity": "sha512-4+zMAmn1DcbYBtFE0pWt6zo8vWoBHTuP/UhtCMTCoGB4sVYvmwRxv9Hc9OpRHSzE9kSl8beD0zKFxuoVHizKQQ==",
+      "license": "MIT",
+      "dependencies": {
+        "@sentry/core": "10.71.0"
+      },
+      "engines": {
+        "node": ">=18"
+      }
+    },
+    "node_modules/@sentry/replay": {
+      "version": "10.71.0",
+      "resolved": "https://registry.npmjs.org/@sentry/replay/-/replay-10.71.0.tgz",
+      "integrity": "sha512-ytEgVg7isvavQL6hgsgYeuSCkcA3EyOKm9lMLQOZTLkiUCtFT/ItWwGNhzS46vQ6wsTv3Uc0Y1JlcJHSFKe/Kg==",
+      "license": "MIT",
+      "dependencies": {
+        "@sentry/browser-utils": "10.71.0",
+        "@sentry/core": "10.71.0"
+      },
+      "engines": {
+        "node": ">=18"
+      }
+    },
+    "node_modules/@sentry/replay-canvas": {
+      "version": "10.71.0",
+      "resolved": "https://registry.npmjs.org/@sentry/replay-canvas/-/replay-canvas-10.71.0.tgz",
+      "integrity": "sha512-YTqesxBh9arExI49LrTm4Y2/xPX40q2GWi0gWRw6lNfYtyNz7/ZfHi8/1N6JEc8dldTslqFhII6ZFecUyU9iaA==",
+      "license": "MIT",
+      "dependencies": {
+        "@sentry/core": "10.71.0",
+        "@sentry/replay": "10.71.0"
+      },
+      "engines": {
+        "node": ">=18"
+      }
+    },
     "node_modules/@sinclair/typebox": {
       "version": "0.34.52",
       "resolved": "https://registry.npmjs.org/@sinclair/typebox/-/typebox-0.34.52.tgz",
diff --git a/package.json b/package.json
index e46e02e8a..7af6e5771 100644
--- a/package.json
+++ b/package.json
@@ -25,6 +25,7 @@
     "@microbit/ui-patterns": "^0.4.0",
     "@sanity/block-content-to-react": "^3.0.0",
     "@sanity/image-url": "^1.0.1",
+    "@sentry/browser": "^10.71.0",
     "@testing-library/jest-dom": "^5.14.1",
     "@testing-library/react": "^14.0.0",
     "@testing-library/user-event": "^14.4.3",
diff --git a/src/App.tsx b/src/App.tsx
index f88690cbd..e4691f06c 100644
--- a/src/App.tsx
+++ b/src/App.tsx
@@ -10,7 +10,11 @@ import "./App.css";
 import { DialogProvider } from "./common/use-dialogs";
 import VisualViewPortCSSVariables from "./common/VisualViewportCSSVariables";
 import { deployment, useDeployment } from "./deployment";
-import { createUSBConnection } from "@microbit/microbit-connection/usb";
+import { ConnectionStatusChange } from "@microbit/microbit-connection";
+import {
+  MicrobitUSBConnection,
+  createUSBConnection,
+} from "@microbit/microbit-connection/usb";
 import { DeviceContextProvider } from "./device/device-hooks";
 import { MockDeviceConnection } from "./device/mock";
 import DocumentationProvider from "./documentation/documentation-hooks";
@@ -21,6 +25,7 @@ import { FileSystemProvider } from "./fs/fs-hooks";
 import { createHost } from "./fs/host";
 import { fetchMicroPython } from "./micropython/micropython";
 import { LanguageServerClientProvider } from "./language-server/language-server-hooks";
+import { logDeviceStatusChange } from "./logging/analytics";
 import { LoggingProvider } from "./logging/logging-hooks";
 import TranslationProvider from "./messages/TranslationProvider";
 import ProjectDropTarget from "./project/ProjectDropTarget";
@@ -38,7 +43,7 @@ const isMockDeviceMode = () =>
   );
 
 const logging = deployment.logging;
-const device = isMockDeviceMode()
+const device: MicrobitUSBConnection = isMockDeviceMode()
   ? new MockDeviceConnection()
   : createUSBConnection({ logging });
 
@@ -50,9 +55,16 @@ fs.initializeInBackground();
 
 const App = () => {
   useEffect(() => {
-    logging.event({ type: "boot" });
+    logging.setUserProperty(
+      "webusb_available",
+      "usb" in navigator ? "yes" : "no"
+    );
+    const statusListener = (event: ConnectionStatusChange) =>
+      logDeviceStatusChange(logging, event);
+    device.addEventListener("status", statusListener);
     device.initialize();
     return () => {
+      device.removeEventListener("status", statusListener);
       device.dispose();
     };
   }, []);
diff --git a/src/common/ErrorBoundary.tsx b/src/common/ErrorBoundary.tsx
index afc097f46..f927ecc7b 100644
--- a/src/common/ErrorBoundary.tsx
+++ b/src/common/ErrorBoundary.tsx
@@ -32,7 +32,7 @@ class ErrorBoundary extends React.Component<
   }
 
   componentDidCatch(error: any, _errorInfo: ErrorInfo) {
-    this.context?.error(error);
+    this.context?.error("Uncaught render error", error);
   }
 
   render() {
diff --git a/src/common/use-action-feedback.tsx b/src/common/use-action-feedback.tsx
index 32722f5c9..990905baa 100644
--- a/src/common/use-action-feedback.tsx
+++ b/src/common/use-action-feedback.tsx
@@ -83,7 +83,7 @@ export class ActionFeedback {
    * @param error the error thrown.
    */
   unexpectedError(error: any) {
-    this.logging.error(error);
+    this.logging.error("Unexpected error", error);
     this.toast({
       title: this.intl.formatMessage({ id: "unexpected-error-description" }),
       status: "error",
diff --git a/src/compliance/stub.tsx b/src/compliance/stub.tsx
new file mode 100644
index 000000000..190075909
--- /dev/null
+++ b/src/compliance/stub.tsx
@@ -0,0 +1,30 @@
+/**
+ * (c) 2026, Micro:bit Educational Foundation and contributors
+ *
+ * SPDX-License-Identifier: MIT
+ */
+import { ReactNode, createContext } from "react";
+import { CookieConsent, DeploymentConfig } from "../deployment";
+
+const stubConsentValue: CookieConsent = {
+  analytics: false,
+  functional: true,
+};
+const stubConsentContext = createContext<CookieConsent | undefined>(
+  stubConsentValue
+);
+
+/**
+ * Compliance for builds without the shared-assets cookie modal (OSS forks,
+ * local dev). Consent is immediately "functional only" so features gated on
+ * having a consent decision, such as the welcome dialog, still work.
+ */
+export const createStubCompliance = (): DeploymentConfig["compliance"] => ({
+  ConsentProvider: ({ children }: { children: ReactNode }) => (
+    <stubConsentContext.Provider value={stubConsentValue}>
+      {children}
+    </stubConsentContext.Provider>
+  ),
+  consentContext: stubConsentContext,
+  manageCookies: undefined,
+});
diff --git a/src/compliance/web.tsx b/src/compliance/web.tsx
new file mode 100644
index 000000000..46c518c72
--- /dev/null
+++ b/src/compliance/web.tsx
@@ -0,0 +1,130 @@
+/**
+ * (c) 2026, Micro:bit Educational Foundation and contributors
+ *
+ * SPDX-License-Identifier: MIT
+ */
+import { ReactNode, createContext, useEffect, useState } from "react";
+import { CookieConsent, DeploymentConfig } from "../deployment";
+import { isStageWithAnalytics } from "../logging/stage";
+
+/**
+ * Surface of the shared-assets `commonConsent` API
+ * (https://shared-assets.microbit.org/common/v2/common.js) that we depend
+ * on. Defined here only to give the compliance code a typed handle on
+ * `window` — the script itself is the authoritative source of behaviour.
+ */
+interface CommonConsent {
+  show: (opts: { userTriggered?: boolean; config: ConsentConfig }) => void;
+  hide: () => void;
+}
+
+interface ConsentConfig {
+  ga: Record<string, never> | undefined;
+  custom: Array<{
+    type: string;
+    category: string;
+    name: string;
+    purpose: string;
+  }>;
+}
+
+type CommonConsentWindow = Window & {
+  commonConsent?: CommonConsent;
+};
+
+/**
+ * Web compliance backed by the shared-assets `commonConsent` API. Shows
+ * the cookie modal, listens for `consentchange`, and exposes a
+ * `manageCookies` callback that re-opens the modal on user request.
+ * Embedded sites (`window.self !== window.top`) assume the parent
+ * handles notices so we no-op there.
+ */
+export const createWebCompliance = (
+  env: Record<string, string>
+): DeploymentConfig["compliance"] => {
+  const consentContext = createContext<CookieConsent | undefined>(undefined);
+
+  const config: ConsentConfig = {
+    ga: isStageWithAnalytics(env.VITE_STAGE) ? {} : undefined,
+    custom: [
+      {
+        type: "session",
+        category: "essential",
+        name: "sessionSettings",
+        purpose: "Used to disable hints based on your prior actions",
+      },
+      {
+        type: "local",
+        category: "essential",
+        name: "release-notice",
+        purpose:
+          "Records which version of the first-time-use notice you've seen so we can decide to show or suppress it in future",
+      },
+      {
+        type: "local",
+        category: "essential",
+        name: "settings",
+        purpose:
+          "Used to store your settings and remember which dialogs you've opted not to be shown in future",
+      },
+    ],
+  };
+
+  const showConsent = (
+    { userTriggered }: { userTriggered: boolean } = { userTriggered: false }
+  ) => {
+    (window as CommonConsentWindow).commonConsent?.show({
+      userTriggered,
+      config,
+    });
+  };
+
+  const hideConsent = () => {
+    (window as CommonConsentWindow).commonConsent?.hide();
+  };
+
+  const manageCookies = () => showConsent({ userTriggered: true });
+
+  const ConsentProvider = ({ children }: { children: ReactNode }) => {
+    const [value, setValue] = useState<CookieConsent | undefined>(undefined);
+    useEffect(() => {
+      // If we're embedded we assume the embedding site is taking
+      // responsibility for required notices to avoid nested cookie modals.
+      if (inIframe()) {
+        return;
+      }
+      const w = window as CommonConsentWindow;
+      const updateListener = (event: Event) => {
+        setValue((event as CustomEvent<CookieConsent>).detail);
+      };
+      const initListener = () => showConsent();
+      w.addEventListener("consentchange", updateListener);
+      if (w.commonConsent) {
+        showConsent();
+      } else {
+        w.addEventListener("consentinit", initListener);
+      }
+      return () => {
+        w.removeEventListener("consentchange", updateListener);
+        w.removeEventListener("consentinit", initListener);
+        hideConsent();
+      };
+    }, []);
+
+    return (
+      <consentContext.Provider value={value}>
+        {children}
+      </consentContext.Provider>
+    );
+  };
+
+  return { ConsentProvider, consentContext, manageCookies };
+};
+
+const inIframe = () => {
+  try {
+    return window.self !== window.top;
+  } catch {
+    return true;
+  }
+};
diff --git a/src/deployment/default/index.tsx b/src/deployment/default/index.tsx
index 0defae214..550713d65 100644
--- a/src/deployment/default/index.tsx
+++ b/src/deployment/default/index.tsx
@@ -3,31 +3,12 @@
  *
  * SPDX-License-Identifier: MIT
  */
-import { ReactNode, createContext } from "react";
-import { CookieConsent, DeploymentConfigFactory } from "..";
-import { ConsoleLogging } from "./logging";
+import { BrandConfigFactory } from "..";
 
-const stubConsentValue: CookieConsent = {
-  analytics: false,
-  functional: true,
-};
-const stubConsentContext = createContext<CookieConsent | undefined>(
-  stubConsentValue
-);
-
-const defaultDeploymentFactory: DeploymentConfigFactory = () => ({
+const defaultBrandFactory: BrandConfigFactory = () => ({
+  product: "python-editor",
   // This isn't ideal as it's the branded version. You can just remove the field to remove the welcome dialog.
   welcomeVideoYouTubeId: "mREwMW69qKc",
-  logging: new ConsoleLogging(),
-  compliance: {
-    ConsentProvider: ({ children }: { children: ReactNode }) => (
-      <stubConsentContext.Provider value={stubConsentValue}>
-        {children}
-      </stubConsentContext.Provider>
-    ),
-    consentContext: stubConsentContext,
-    manageCookies: undefined,
-  },
 });
 
-export default defaultDeploymentFactory;
+export default defaultBrandFactory;
diff --git a/src/deployment/default/logging.ts b/src/deployment/default/logging.ts
index b71a88029..8c7853e89 100644
--- a/src/deployment/default/logging.ts
+++ b/src/deployment/default/logging.ts
@@ -5,14 +5,22 @@
  */
 import { Event, Logging } from "../../logging/logging";
 
+/**
+ * Console-only logging for tests and the NullLoggingProvider. The app
+ * itself always uses Logger (see src/deployment/index.ts), which also
+ * falls back to the console when no analytics or Sentry are configured.
+ */
 export class ConsoleLogging implements Logging {
   event(event: Event): void {
     console.log(event);
   }
-  error(e: any): void {
-    console.error(e);
+  error(message: string, e: unknown): void {
+    console.error(message, e);
   }
   log(e: any): void {
     console.log(e);
   }
+  setUserProperty(name: string, value: string): void {
+    console.log("[ConsoleLogging] setUserProperty:", name, value);
+  }
 }
diff --git a/src/deployment/index.ts b/src/deployment/index.ts
index f889029bf..46f0f9d96 100644
--- a/src/deployment/index.ts
+++ b/src/deployment/index.ts
@@ -3,27 +3,50 @@
  *
  * SPDX-License-Identifier: MIT
  */
-import { ReactNode, useContext } from "react";
+import React, { ReactNode, useContext } from "react";
+import { createStubCompliance } from "../compliance/stub";
+import { createWebCompliance } from "../compliance/web";
+import { Logger } from "../logging/logger";
 import { Logging } from "../logging/logging";
-
-export type DeploymentConfigFactory = (
-  env: Record<string, string>
-) => DeploymentConfig;
+import { WebSink } from "../logging/sink";
 
 // This is configured via a vite alias, defaulting to ./default
 import { default as df } from "theme-package";
-const deploymentFactory: DeploymentConfigFactory = df;
-export const deployment = deploymentFactory(import.meta.env);
+
+/**
+ * Brand-and-content config supplied by the (optionally private) theme
+ * package. No analytics opinions live here — the OSS deployment loader
+ * picks the logger and compliance backend based on build config and env.
+ */
+export interface BrandConfig {
+  /**
+   * Stable analytics identifier slug for this product. Attached as
+   * the `product` param on every event the logger emits, so dashboards
+   * can split traffic by product when multiple sibling apps share a
+   * GA4 property.
+   */
+  product: string;
+  welcomeVideoYouTubeId?: string;
+  squareLogo?: ReactNode;
+  horizontalLogo?: ReactNode;
+
+  supportLink?: string;
+  guideLink?: string;
+  userGuideLink?: string;
+  accessibilityLink?: string;
+  termsOfUseLink?: string;
+  privacyPolicyLink?: string;
+  translationLink?: string;
+}
+
+export type BrandConfigFactory = (env: Record<string, string>) => BrandConfig;
 
 export interface CookieConsent {
   analytics: boolean;
   functional: boolean;
 }
 
-export interface DeploymentConfig {
-  welcomeVideoYouTubeId?: string;
-  squareLogo?: ReactNode;
-  horizontalLogo?: ReactNode;
+export interface DeploymentConfig extends BrandConfig {
   compliance: {
     /**
      * A provider that will be used to wrap the app UI.
@@ -39,22 +62,37 @@ export interface DeploymentConfig {
      */
     manageCookies: (() => void) | undefined;
   };
-
-  supportLink?: string;
-  guideLink?: string;
-  userGuideLink?: string;
-  accessibilityLink?: string;
-  termsOfUseLink?: string;
-  privacyPolicyLink?: string;
-  translationLink?: string;
-
   logging: Logging;
 }
 
+const brandFactory: BrandConfigFactory = df;
+
+const createLogging = (env: Record<string, string>, product: string): Logging =>
+  // WebSink is silent without gtag and Logger falls back to console
+  // breadcrumbs without a Sentry DSN, so this is safe for every build.
+  new Logger(new WebSink(), env, product);
+
+const createCompliance = (
+  env: Record<string, string>
+): DeploymentConfig["compliance"] =>
+  // The same flag index.html uses to decide whether to load the
+  // shared-assets script that provides the cookie modal (and gtag).
+  env.VITE_FOUNDATION_BUILD === "true"
+    ? createWebCompliance(env)
+    : createStubCompliance();
+
+export const deployment: DeploymentConfig = (() => {
+  const env = import.meta.env as unknown as Record<string, string>;
+  const brand = brandFactory(env);
+  return {
+    ...brand,
+    logging: createLogging(env, brand.product),
+    compliance: createCompliance(env),
+  };
+})();
+
 // eslint-disable-next-line @eslint-react/no-unnecessary-use-prefix -- hook-shaped by design and used as one throughout
-export const useDeployment = (): DeploymentConfig => {
-  return deployment;
-};
+export const useDeployment = (): DeploymentConfig => deployment;
 
 export const useCookieConsent = (): CookieConsent | undefined => {
   const { compliance } = useDeployment();
diff --git a/src/device/device-hooks.tsx b/src/device/device-hooks.tsx
index facf5726d..13a8b67ba 100644
--- a/src/device/device-hooks.tsx
+++ b/src/device/device-hooks.tsx
@@ -192,7 +192,7 @@ export const useDeviceTraceback = () => {
       setRuntimeError((current) => {
         if (!current && latest) {
           logging.event({
-            type: "serial-traceback",
+            type: "serial_traceback",
           });
         }
         return latest;
diff --git a/src/device/simulator.ts b/src/device/simulator.ts
index fb205b145..20d5cfa41 100644
--- a/src/device/simulator.ts
+++ b/src/device/simulator.ts
@@ -186,7 +186,7 @@ export class SimulatorDeviceConnection
       case "request_flash": {
         this.dispatchEvent("requestflash");
         this.logging.event({
-          type: "sim-user-start",
+          type: "sim_start",
         });
         break;
       }
@@ -244,7 +244,7 @@ export class SimulatorDeviceConnection
       }
       case "internal_error": {
         const error = event.data.error;
-        this.logging.error(error);
+        this.logging.error("Simulator internal error", error);
         break;
       }
       default: {
@@ -264,7 +264,8 @@ export class SimulatorDeviceConnection
   private logSensor(sensorId: string): void {
     if (!this.sensorsLogged[sensorId]) {
       this.logging.event({
-        type: `sim-user-${sensorId}`,
+        type: "sim_sensor",
+        detail: { id: sensorId },
       });
       this.sensorsLogged[sensorId] = true;
     }
@@ -365,21 +366,23 @@ export class SimulatorDeviceConnection
     this.postMessage("reset", {});
     this.notifyResetComms();
     this.logging.event({
-      type: "sim-user-reset",
+      type: "sim_reset",
     });
   };
 
   mute = async (): Promise<void> => {
     this.postMessage("mute", {});
     this.logging.event({
-      type: "sim-user-mute",
+      type: "sim_audio",
+      detail: { state: "mute" },
     });
   };
 
   unmute = async (): Promise<void> => {
     this.postMessage("unmute", {});
     this.logging.event({
-      type: "sim-user-unmute",
+      type: "sim_audio",
+      detail: { state: "unmute" },
     });
   };
 
diff --git a/src/documentation/api/ApiDocumentation.tsx b/src/documentation/api/ApiDocumentation.tsx
index ef6db311f..4bb5ba7e3 100644
--- a/src/documentation/api/ApiDocumentation.tsx
+++ b/src/documentation/api/ApiDocumentation.tsx
@@ -30,7 +30,7 @@ export const ApiDocumentation = ({ docs }: ApiDocumentationProps) => {
   const [anchor, setAnchor] = useRouterTabSlug("api");
   const handleNavigate = useCallback(
     (id: string | undefined) => {
-      setAnchor(id ? { id } : undefined, "documentation-user");
+      setAnchor(id ? { id } : undefined, "user");
     },
     [setAnchor]
   );
diff --git a/src/documentation/api/ApiNode.tsx b/src/documentation/api/ApiNode.tsx
index 76b2405d2..dfa3901a9 100644
--- a/src/documentation/api/ApiNode.tsx
+++ b/src/documentation/api/ApiNode.tsx
@@ -415,7 +415,8 @@ const getDragPasteData = (fullName: string, kind: string): PasteContext => {
     code,
     codeWithImports: full,
     type: kind === "function" ? "call" : "example",
-    id: `api-${fullName}`,
+    tab: "api",
+    id: fullName,
   };
 };
 
@@ -443,14 +444,14 @@ const DraggableSignature = ({
   docs,
   css: cssProp,
 }: DraggableSignatureProps) => {
-  const { fullName, kind, name, id } = docs;
+  const { fullName, kind, name } = docs;
   const logging = useLogging();
   const dragImage = useCodeDragImage();
   const handleDragStart = useCallback(
     (event: React.DragEvent) => {
       logging.event({
-        type: "code-drag",
-        message: `api-${id}`,
+        type: "code_drag",
+        detail: { surface: "api", id: fullName },
       });
       dndDebug("dragstart");
       event.dataTransfer.dropEffect = "copy";
@@ -461,7 +462,7 @@ const DraggableSignature = ({
         event.dataTransfer.setDragImage(dragImage.current, 0, 0);
       }
     },
-    [fullName, kind, id, dragImage, logging]
+    [fullName, kind, dragImage, logging]
   );
 
   const handleDragEnd = useCallback((_event: React.DragEvent) => {
@@ -477,8 +478,8 @@ const DraggableSignature = ({
   const { onCopy } = useClipboard(code);
   const handleCopyCode = useCallback(async () => {
     onCopy();
-    await actions?.copyCode(code, codeWithImports, type, id);
-  }, [actions, code, codeWithImports, onCopy, type, id]);
+    await actions?.copyCode(code, codeWithImports, type, fullName, "api");
+  }, [actions, code, codeWithImports, onCopy, type, fullName]);
   const hotKeysRef = useHotkeys(keyboardShortcuts.copyCode, handleCopyCode, {
     preventDefault: true,
   });
diff --git a/src/documentation/common/CodeEmbed.tsx b/src/documentation/common/CodeEmbed.tsx
index 9f72e87b1..105f3eb25 100644
--- a/src/documentation/common/CodeEmbed.tsx
+++ b/src/documentation/common/CodeEmbed.tsx
@@ -118,7 +118,8 @@ const CodeEmbed = ({
       code,
       codeWithImports,
       "example",
-      `${toolkitType}-${parentSlug}`
+      parentSlug,
+      toolkitType
     );
   }, [actions, code, codeWithImports, onCopy, parentSlug, toolkitType]);
   const projectActions = useProjectActions();
@@ -269,15 +270,16 @@ const Code = React.forwardRef<HTMLDivElement, CodeProps>(
     const handleDragStart = useCallback(
       (event: React.DragEvent) => {
         logging.event({
-          type: "code-drag",
-          message: `${toolkitType}-${parentSlug}`,
+          type: "code_drag",
+          detail: { surface: toolkitType, id: parentSlug },
         });
         dndDebug("dragstart");
         event.dataTransfer.dropEffect = "copy";
         setDragContext({
           code: full,
           type: "example",
-          id: `${toolkitType}-${parentSlug}`,
+          tab: toolkitType,
+          id: parentSlug,
         });
         event.dataTransfer.setData(pythonSnippetMediaType, full);
         if (dragImage.current) {
diff --git a/src/documentation/common/DocumentationContent.tsx b/src/documentation/common/DocumentationContent.tsx
index 75fba63e6..1846ac01c 100644
--- a/src/documentation/common/DocumentationContent.tsx
+++ b/src/documentation/common/DocumentationContent.tsx
@@ -104,7 +104,7 @@ const DocumentationInternalLinkMark = (
               id: props.mark.slug.current,
             },
           },
-          "documentation-user"
+          "user"
         );
       }}
     >
diff --git a/src/documentation/documentation-hooks.tsx b/src/documentation/documentation-hooks.tsx
index 03071dd83..d1c0bde6a 100644
--- a/src/documentation/documentation-hooks.tsx
+++ b/src/documentation/documentation-hooks.tsx
@@ -47,7 +47,7 @@ const useContent = <T,>(
           setState({ status: "ok", content, languageId });
         }
       } catch (e) {
-        logging.error(e);
+        logging.error("Failed to load documentation", e);
         if (!ignore) {
           setState({
             status: "error",
diff --git a/src/documentation/ideas/IdeasDocumentation.tsx b/src/documentation/ideas/IdeasDocumentation.tsx
index 6502f6fca..7a6db029e 100644
--- a/src/documentation/ideas/IdeasDocumentation.tsx
+++ b/src/documentation/ideas/IdeasDocumentation.tsx
@@ -42,7 +42,7 @@ const IdeasDocumentation = ({ ideas }: IdeasDocumentationProps) => {
   const ideaId = anchor?.id;
   const handleNavigate = useCallback(
     (ideaId: string | undefined) => {
-      setAnchor(ideaId ? { id: ideaId } : undefined, "documentation-user");
+      setAnchor(ideaId ? { id: ideaId } : undefined, "user");
     },
     [setAnchor]
   );
diff --git a/src/documentation/reference/ReferenceDocumentation.tsx b/src/documentation/reference/ReferenceDocumentation.tsx
index a45face59..62d515de9 100644
--- a/src/documentation/reference/ReferenceDocumentation.tsx
+++ b/src/documentation/reference/ReferenceDocumentation.tsx
@@ -35,10 +35,7 @@ const ReferenceToolkit = ({ toolkit }: ReferenceDocumentationProps) => {
   const topicOrEntryId = anchor?.id.split("/")[0];
   const handleNavigate = useCallback(
     (topicOrEntryId: string | undefined) => {
-      setAnchor(
-        topicOrEntryId ? { id: topicOrEntryId } : undefined,
-        "documentation-user"
-      );
+      setAnchor(topicOrEntryId ? { id: topicOrEntryId } : undefined, "user");
     },
     [setAnchor]
   );
diff --git a/src/documentation/search/search-hooks.tsx b/src/documentation/search/search-hooks.tsx
index 0fc140ed1..fed25d84d 100644
--- a/src/documentation/search/search-hooks.tsx
+++ b/src/documentation/search/search-hooks.tsx
@@ -73,7 +73,7 @@ const SearchProvider = ({ children }: { children: ReactNode }) => {
           if (!isUnmounted()) {
             setResults((prevResults) => {
               if (!prevResults) {
-                logging.event({ type: "search" });
+                logging.event({ type: "docs_search" });
               }
               return results;
             });
diff --git a/src/editor/ZoomControls.tsx b/src/editor/ZoomControls.tsx
index 9501f18fb..3441945d8 100644
--- a/src/editor/ZoomControls.tsx
+++ b/src/editor/ZoomControls.tsx
@@ -32,14 +32,14 @@ const ZoomControls = ({ size, css: cssProp }: ZoomControlsProps) => {
       ...settings,
       fontSize: Math.min(maximumFontSize, settings.fontSize + fontSizeStep),
     });
-    logging.event({ type: "zoom-in" });
+    logging.event({ type: "editor_zoom", detail: { direction: "in" } });
   }, [setSettings, settings, logging]);
   const handleZoomOut = useCallback(() => {
     setSettings({
       ...settings,
       fontSize: Math.max(minimumFontSize, settings.fontSize - fontSizeStep),
     });
-    logging.event({ type: "zoom-out" });
+    logging.event({ type: "editor_zoom", detail: { direction: "out" } });
   }, [setSettings, settings, logging]);
   const intl = useIntl();
   return (
diff --git a/src/editor/active-editor-hooks.tsx b/src/editor/active-editor-hooks.tsx
index 8e59644ab..83f42e844 100644
--- a/src/editor/active-editor-hooks.tsx
+++ b/src/editor/active-editor-hooks.tsx
@@ -35,16 +35,18 @@ export class EditorActions {
     code: string,
     codeWithImports: string,
     type: CodeInsertType,
-    id?: string
+    id?: string,
+    tab?: string
   ): Promise<void> => {
     this.logging.event({
-      type: "code-copy",
-      message: id,
+      type: "code_copy",
+      detail: { surface: tab, id },
     });
     copyCodeSnippet({
       code,
       codeWithImports,
       type,
+      tab,
       id,
     });
     this.actionFeedback.success({
@@ -53,14 +55,14 @@ export class EditorActions {
   };
   undo = (): void => {
     this.logging.event({
-      type: "undo",
+      type: "editor_undo",
     });
     undo(this.view);
     this.view.focus();
   };
   redo = (): void => {
     this.logging.event({
-      type: "redo",
+      type: "editor_redo",
     });
     redo(this.view);
     this.view.focus();
diff --git a/src/editor/codemirror/CodeMirror.tsx b/src/editor/codemirror/CodeMirror.tsx
index f6b95ad74..b3c6c2e3c 100644
--- a/src/editor/codemirror/CodeMirror.tsx
+++ b/src/editor/codemirror/CodeMirror.tsx
@@ -268,7 +268,7 @@ const CodeMirror = ({
           tab,
           slug: { id },
         },
-        "documentation-from-code"
+        "code"
       );
       const view = viewRef.current!;
       // Put the focus back in the text editor so the docs are immediately useful.
@@ -306,8 +306,8 @@ const logPastedLineCount = (logging: Logging, update: ViewUpdate) => {
             new TextEncoder().encode(inserted.toString().trim())
           );
           logging.event({
-            type: "paste",
-            value: lineCount,
+            type: "editor_paste",
+            detail: { count: lineCount },
           });
         }
       )
diff --git a/src/editor/codemirror/copypaste.ts b/src/editor/codemirror/copypaste.ts
index d1cf91f74..d6f6bd823 100644
--- a/src/editor/codemirror/copypaste.ts
+++ b/src/editor/codemirror/copypaste.ts
@@ -13,6 +13,10 @@ export interface PasteContext {
   code: string;
   codeWithImports: string;
   type: CodeInsertType;
+  /**
+   * Analytics identity of the snippet, as for DragContext.
+   */
+  tab?: string;
   id?: string;
 }
 
@@ -47,8 +51,8 @@ const copyPasteHandlers = () => [
       }
       event.preventDefault();
       deployment.logging.event({
-        type: "code-paste",
-        message: pasteContext.id,
+        type: "code_paste",
+        detail: { surface: pasteContext.tab, id: pasteContext.id },
       });
 
       const line = view.state.doc.lineAt(view.state.selection.ranges[0].from);
diff --git a/src/editor/codemirror/dnd.ts b/src/editor/codemirror/dnd.ts
index de893048f..e7b7de3fd 100644
--- a/src/editor/codemirror/dnd.ts
+++ b/src/editor/codemirror/dnd.ts
@@ -51,6 +51,11 @@ export type CodeInsertType =
 export interface DragContext {
   code: string;
   type: CodeInsertType;
+  /**
+   * Analytics identity of the snippet: the documentation tab it came from
+   * and its slug / API name. See code_drag / code_drop.
+   */
+  tab?: string;
   id?: string;
 }
 
@@ -183,8 +188,8 @@ const dndHandlers = ({ sessionSettings, setSessionSettings }: DragTracker) => {
           return;
         }
         deployment.logging.event({
-          type: "code-drop",
-          message: dragContext.id,
+          type: "code_drop",
+          detail: { surface: dragContext.tab, id: dragContext.id },
         });
         if (!sessionSettings.dragDropSuccess) {
           setSessionSettings({
diff --git a/src/editor/codemirror/language-server/autocompletion.test.ts b/src/editor/codemirror/language-server/autocompletion.test.ts
index 4d8910f6a..c544ebaf3 100644
--- a/src/editor/codemirror/language-server/autocompletion.test.ts
+++ b/src/editor/codemirror/language-server/autocompletion.test.ts
@@ -30,6 +30,7 @@ const createLogging = (): Logging => ({
   event: vi.fn(),
   error: vi.fn(),
   log: vi.fn(),
+  setUserProperty: vi.fn(),
 });
 
 const createClient = (
@@ -233,7 +234,7 @@ describe("createCompletionSource", () => {
       expect(state.doc.toString()).toEqual("button_a");
       expect(state.selection.main.from).toEqual("button_a".length);
       expect(logging.event).toHaveBeenCalledWith({
-        type: "autocomplete-accept",
+        type: "editor_autocomplete",
       });
     });
 
diff --git a/src/editor/codemirror/language-server/autocompletion.ts b/src/editor/codemirror/language-server/autocompletion.ts
index 14a9e6d66..dd12edc80 100644
--- a/src/editor/codemirror/language-server/autocompletion.ts
+++ b/src/editor/codemirror/language-server/autocompletion.ts
@@ -108,7 +108,7 @@ export const createCompletionSource =
               // In practice we don't get textEdit fields back from Pyright so the label is used.
               label: item.label,
               apply: (view, completion, from, to) => {
-                logging.event({ type: "autocomplete-accept" });
+                logging.event({ type: "editor_autocomplete" });
                 const insert = item.label;
                 const transactions: TransactionSpec[] = [
                   {
diff --git a/src/fs/fs.test.ts b/src/fs/fs.test.ts
index 1ad7e97e1..baa8cc299 100644
--- a/src/fs/fs.test.ts
+++ b/src/fs/fs.test.ts
@@ -228,7 +228,8 @@ describe("Filesystem", () => {
   it("gives useful stats", async () => {
     expect(await ufs.statistics()).toEqual({
       files: 1,
-      lines: undefined, // signifies initial program
+      lines: expect.any(Number),
+      defaultMain: true,
       storageUsed: 256,
       magicModules: 0,
     });
@@ -246,6 +247,7 @@ describe("Filesystem", () => {
     expect(await ufs.statistics()).toEqual({
       files: 3,
       lines: 3,
+      defaultMain: false,
       storageUsed: 896,
       magicModules: 1,
     });
diff --git a/src/fs/fs.ts b/src/fs/fs.ts
index c381b39c2..c032246fb 100644
--- a/src/fs/fs.ts
+++ b/src/fs/fs.ts
@@ -46,10 +46,12 @@ export enum VersionAction {
 export interface Statistics {
   /**
    * The number of lines in main.py.
-   *
-   * Undefined when it is unchanged from the default program.
    */
-  lines: number | undefined;
+  lines: number;
+  /**
+   * Whether main.py is unchanged from the default program.
+   */
+  defaultMain: boolean;
   /**
    * File count.
    */
@@ -415,12 +417,10 @@ export class FileSystem extends TypedEventTarget<EventMap> {
     return {
       files: files.length,
       storageUsed: fs.getStorageUsed(),
-      lines:
-        this.cachedInitialProject &&
-        this.cachedInitialProject.files[MAIN_FILE] ===
-          fromByteArray(currentMainFile)
-          ? undefined
-          : lineNumFromUint8Array(currentMainFile),
+      lines: lineNumFromUint8Array(currentMainFile),
+      defaultMain:
+        this.cachedInitialProject?.files[MAIN_FILE] ===
+        fromByteArray(currentMainFile),
       magicModules: numMagicModules,
     };
   }
diff --git a/src/fs/host.ts b/src/fs/host.ts
index 0ad04cb1b..37480617f 100644
--- a/src/fs/host.ts
+++ b/src/fs/host.ts
@@ -165,7 +165,8 @@ const getControllerHost = (logging: Logging): Window | undefined => {
       return window.parent;
     }
     logging.error(
-      "Cannot detect valid host controller despite controller URL parameter."
+      "Cannot detect valid host controller despite controller URL parameter.",
+      new Error("No parent window")
     );
   }
 };
diff --git a/src/fs/storage.test.ts b/src/fs/storage.test.ts
index 9b5b7f1fe..afbb52d1c 100644
--- a/src/fs/storage.test.ts
+++ b/src/fs/storage.test.ts
@@ -129,7 +129,9 @@ describe("SplitStrategyStorage", () => {
     // After encoding this is big enough to hit the 5MB limit. Note that Safari is half this.
     await split.write("test2.py", new Uint8Array(3_800_000));
 
-    expect(log.errors[0]).toEqual("Abandoning secondary storage due to error");
+    expect(log.errors[0].message).toEqual(
+      "Abandoning secondary storage due to error"
+    );
     expect(await session.ls()).toEqual([]);
     expect(await memory.ls()).toEqual(["test1.py", "test2.py"]);
 
diff --git a/src/fs/storage.ts b/src/fs/storage.ts
index 7cc25d06b..90ed81333 100644
--- a/src/fs/storage.ts
+++ b/src/fs/storage.ts
@@ -269,12 +269,13 @@ export class SplitStrategyStorage implements FSStorage {
         await this.secondary.clear();
       } catch (e2) {
         // Not much we can do.
-        this.log.error("Failed to clear secondary storage in error scenario");
-        this.log.error(e2);
+        this.log.error(
+          "Failed to clear secondary storage in error scenario",
+          e2
+        );
       }
       // Avoid all future errors this session.
-      this.log.error("Abandoning secondary storage due to error");
-      this.log.error(e1);
+      this.log.error("Abandoning secondary storage due to error", e1);
       this.secondary = undefined;
     }
   }
diff --git a/src/logging/analytics.test.ts b/src/logging/analytics.test.ts
new file mode 100644
index 000000000..124afcd7b
--- /dev/null
+++ b/src/logging/analytics.test.ts
@@ -0,0 +1,98 @@
+/**
+ * (c) 2026, Micro:bit Educational Foundation and contributors
+ *
+ * SPDX-License-Identifier: MIT
+ */
+import { ConnectionStatus, DeviceError } from "@microbit/microbit-connection";
+import { beforeEach, describe, expect, it } from "vitest";
+import {
+  deviceFailureCode,
+  importFormat,
+  logDeviceStatusChange,
+  markUserDisconnect,
+} from "./analytics";
+import { MockLogging } from "./mock";
+
+const file = (name: string) => new File([""], name);
+
+describe("importFormat", () => {
+  it("classifies by extension, case-insensitively", () => {
+    expect(importFormat([file("a.hex")])).toEqual("hex");
+    expect(importFormat([file("A.HEX")])).toEqual("hex");
+    expect(importFormat([file("main.py")])).toEqual("py");
+    expect(importFormat([file("data.csv")])).toEqual("other");
+    expect(importFormat([file("noextension")])).toEqual("other");
+  });
+
+  it("reports multiple files regardless of type", () => {
+    expect(importFormat([file("a.py"), file("b.py")])).toEqual("multiple");
+  });
+});
+
+describe("deviceFailureCode", () => {
+  it("uses the DeviceError code", () => {
+    expect(
+      deviceFailureCode(new DeviceError({ code: "device-in-use" }))
+    ).toEqual("device-in-use");
+  });
+
+  it("falls back to unknown for other errors", () => {
+    expect(deviceFailureCode(new Error("boom"))).toEqual("unknown");
+    expect(deviceFailureCode(undefined)).toEqual("unknown");
+  });
+});
+
+describe("logDeviceStatusChange", () => {
+  let logging: MockLogging;
+  beforeEach(() => {
+    logging = new MockLogging();
+    markUserDisconnect(false);
+  });
+
+  it("reports an unexpected drop from Connected", () => {
+    logDeviceStatusChange(logging, {
+      previousStatus: ConnectionStatus.Connected,
+      status: ConnectionStatus.Disconnected,
+    });
+    expect(logging.events).toEqual([
+      {
+        type: "device_disconnect",
+        detail: { reason: "unknown", transport: "web_usb" },
+      },
+    ]);
+  });
+
+  it("treats loss of authorization from Connected as a drop", () => {
+    logDeviceStatusChange(logging, {
+      previousStatus: ConnectionStatus.Connected,
+      status: ConnectionStatus.NoAuthorizedDevice,
+    });
+    expect(logging.events).toHaveLength(1);
+  });
+
+  it("ignores transitions that are not from Connected", () => {
+    logDeviceStatusChange(logging, {
+      previousStatus: ConnectionStatus.Connecting,
+      status: ConnectionStatus.Disconnected,
+    });
+    logDeviceStatusChange(logging, {
+      previousStatus: ConnectionStatus.Connected,
+      status: ConnectionStatus.Paused,
+    });
+    expect(logging.events).toEqual([]);
+  });
+
+  it("suppresses the status change that follows a user disconnect, once", () => {
+    markUserDisconnect(true);
+    logDeviceStatusChange(logging, {
+      previousStatus: ConnectionStatus.Connected,
+      status: ConnectionStatus.Disconnected,
+    });
+    expect(logging.events).toEqual([]);
+    logDeviceStatusChange(logging, {
+      previousStatus: ConnectionStatus.Connected,
+      status: ConnectionStatus.Disconnected,
+    });
+    expect(logging.events).toHaveLength(1);
+  });
+});
diff --git a/src/logging/analytics.ts b/src/logging/analytics.ts
new file mode 100644
index 000000000..64f35018d
--- /dev/null
+++ b/src/logging/analytics.ts
@@ -0,0 +1,92 @@
+/**
+ * (c) 2026, Micro:bit Educational Foundation and contributors
+ *
+ * SPDX-License-Identifier: MIT
+ */
+import {
+  ConnectionStatus,
+  ConnectionStatusChange,
+  DeviceError,
+} from "@microbit/microbit-connection";
+import { Logging } from "./logging";
+
+/**
+ * Shared vocabulary for the device_* events. See docs/analytics-events.md.
+ *
+ * `transport` describes the user's hardware setup. The editor only
+ * connects over WebUSB, so it's a constant here; ml-trainer emits
+ * `web_bluetooth` / `native_bluetooth` / `radio` for the same param.
+ */
+export const transport = "web_usb";
+
+/**
+ * Which user goal the device event belongs to: `connect` for the Connect
+ * button (serial / REPL plus fast flashing) or `download` for Send to
+ * micro:bit, including any connection it had to establish first.
+ */
+export type AnalyticsTask = "connect" | "download";
+
+export type ImportFormat = "hex" | "py" | "other" | "multiple";
+
+/**
+ * The `format` param for project_import. Extension-based because the
+ * event counts attempts and fires before the files are parsed.
+ */
+export const importFormat = (files: File[]): ImportFormat => {
+  if (files.length > 1) {
+    return "multiple";
+  }
+  const parts = files[0].name.toLowerCase().split(".");
+  const extension = parts.length > 1 ? parts[parts.length - 1] : "";
+  switch (extension) {
+    case "hex":
+      return "hex";
+    case "py":
+      return "py";
+    default:
+      return "other";
+  }
+};
+
+/**
+ * The `code` param for device_failure.
+ */
+export const deviceFailureCode = (e: unknown): string =>
+  e instanceof DeviceError ? e.code : "unknown";
+
+// Set by the user-initiated disconnect action so the status listener
+// below doesn't also report the resulting status change as an
+// unexpected disconnect.
+let userDisconnectPending = false;
+
+export const markUserDisconnect = (pending: boolean): void => {
+  userDisconnectPending = pending;
+};
+
+/**
+ * Emit device_disconnect with reason `unknown` when a connected device
+ * goes away other than via the Disconnect button (unplugged, reset,
+ * browser revoked access). Wire to the device's "status" event.
+ */
+export const logDeviceStatusChange = (
+  logging: Logging,
+  change: ConnectionStatusChange
+): void => {
+  if (change.previousStatus !== ConnectionStatus.Connected) {
+    return;
+  }
+  if (
+    change.status !== ConnectionStatus.Disconnected &&
+    change.status !== ConnectionStatus.NoAuthorizedDevice
+  ) {
+    return;
+  }
+  const user = userDisconnectPending;
+  userDisconnectPending = false;
+  if (!user) {
+    logging.event({
+      type: "device_disconnect",
+      detail: { reason: "unknown", transport },
+    });
+  }
+};
diff --git a/src/logging/logger.test.ts b/src/logging/logger.test.ts
new file mode 100644
index 000000000..6de3b507f
--- /dev/null
+++ b/src/logging/logger.test.ts
@@ -0,0 +1,85 @@
+/**
+ * (c) 2026, Micro:bit Educational Foundation and contributors
+ *
+ * SPDX-License-Identifier: MIT
+ */
+import { beforeEach, describe, expect, it, vi } from "vitest";
+import { Logger } from "./logger";
+import { AnalyticsParams, AnalyticsSink } from "./sink";
+
+class RecordingSink implements AnalyticsSink {
+  events: Array<{ name: string; params: AnalyticsParams }> = [];
+  userProperties: Record<string, string> = {};
+  event(name: string, params: AnalyticsParams): void {
+    this.events.push({ name, params });
+  }
+  setUserProperty(name: string, value: string): void {
+    this.userProperties[name] = value;
+  }
+}
+
+describe("Logger", () => {
+  let sink: RecordingSink;
+  let logger: Logger;
+
+  beforeEach(() => {
+    // No Sentry DSN: breadcrumbs fall back to console.log.
+    vi.spyOn(console, "log").mockImplementation(() => {});
+    sink = new RecordingSink();
+    logger = new Logger(sink, {}, "python-editor");
+  });
+
+  it("flattens primitive detail fields into params and injects product", () => {
+    logger.event({
+      type: "project_save",
+      detail: { format: "hex", files: 3, is_default: false },
+    });
+    expect(sink.events).toEqual([
+      {
+        name: "project_save",
+        params: {
+          format: "hex",
+          files: 3,
+          is_default: false,
+          product: "python-editor",
+        },
+      },
+    ]);
+  });
+
+  it("drops non-primitive and undefined detail values", () => {
+    logger.event({
+      type: "docs_navigate",
+      detail: { via: "user", surface: "reference", id: undefined, nested: {} },
+    });
+    expect(sink.events[0].params).toEqual({
+      via: "user",
+      surface: "reference",
+      product: "python-editor",
+    });
+  });
+
+  it("lets top-level message and value win over detail keys", () => {
+    logger.event({
+      type: "x",
+      message: "top",
+      value: 2,
+      detail: { message: "detail", value: 1 },
+    });
+    expect(sink.events[0].params).toEqual({
+      message: "top",
+      value: 2,
+      product: "python-editor",
+    });
+  });
+
+  it("sends events with no detail as product only", () => {
+    logger.event({ type: "docs_search" });
+    expect(sink.events[0].params).toEqual({ product: "python-editor" });
+  });
+
+  it("passes user properties to the sink", () => {
+    logger.setUserProperty("webusb_available", "yes");
+    expect(sink.userProperties).toEqual({ webusb_available: "yes" });
+  });
+});
diff --git a/src/logging/logger.ts b/src/logging/logger.ts
new file mode 100644
index 000000000..353fa692d
--- /dev/null
+++ b/src/logging/logger.ts
@@ -0,0 +1,84 @@
+/**
+ * (c) 2026, Micro:bit Educational Foundation and contributors
+ *
+ * SPDX-License-Identifier: MIT
+ */
+import { Event, Logging } from "./logging";
+import { initSentry, reportBreadcrumb, reportError } from "./sentry";
+import { AnalyticsParams, AnalyticsSink } from "./sink";
+
+/**
+ * Standard Logging implementation: handles the cross-cutting concerns
+ * (Sentry init / error capture / event breadcrumbs, param building,
+ * product injection, console.log) and delegates the analytics SDK calls
+ * to an AnalyticsSink.
+ *
+ * Events are sent in GA4-native shape (name + flat params) — call-site
+ * `detail` fields become event params directly. See
+ * docs/analytics-events.md for the catalogue.
+ */
+export class Logger implements Logging {
+  private sentryDsn: string | undefined;
+
+  constructor(
+    private sink: AnalyticsSink,
+    env: Record<string, string>,
+    private product: string
+  ) {
+    this.sentryDsn = initSentry(env);
+  }
+
+  event(event: Event): void {
+    this.sink.event(event.type, this.buildParams(event));
+    reportBreadcrumb(this.sentryDsn, "Event", {
+      type: event.type,
+      message: event.message,
+      value: event.value,
+      detail: event.detail as unknown,
+    });
+  }
+
+  setUserProperty(name: string, value: string): void {
+    this.sink.setUserProperty(name, value);
+  }
+
+  error(message: string, e: unknown): void {
+    reportError(this.sentryDsn, message, e);
+  }
+
+  log(v: unknown): void {
+    console.log(v);
+  }
+
+  private buildParams(event: Event): AnalyticsParams {
+    const params: AnalyticsParams = {};
+    if (
+      event.detail !== undefined &&
+      typeof event.detail === "object" &&
+      event.detail !== null
+    ) {
+      for (const [k, v] of Object.entries(
+        event.detail as Record<string, unknown>
+      )) {
+        if (isPrimitive(v)) {
+          params[k] = v;
+        }
+      }
+    }
+    // Top-level fields set last so they can't be shadowed by detail
+    // keys of the same name.
+    if (event.message !== undefined) {
+      params.message = event.message;
+    }
+    if (event.value !== undefined) {
+      params.value = event.value;
+    }
+    // Product is injected here so it lands on every event without
+    // call sites having to pass it. See BrandConfig.product.
+    params.product = this.product;
+    return params;
+  }
+}
+
+const isPrimitive = (v: unknown): v is string | number | boolean =>
+  typeof v === "string" || typeof v === "number" || typeof v === "boolean";
diff --git a/src/logging/logging.ts b/src/logging/logging.ts
index fe7c8ca4f..c208c29ca 100644
--- a/src/logging/logging.ts
+++ b/src/logging/logging.ts
@@ -12,6 +12,12 @@ export interface Event {
 
 export interface Logging {
   event(event: Event): void;
-  error(e: any): void;
+  error(message: string, e: unknown): void;
   log(e: any): void;
+  /**
+   * Set a GA4 user property — auto-attaches to every subsequent event
+   * for the same user. Set early (e.g. on app boot) so events fired
+   * after are queryable by it.
+   */
+  setUserProperty(name: string, value: string): void;
 }
diff --git a/src/logging/mock.ts b/src/logging/mock.ts
index 16213809a..2bae8d35f 100644
--- a/src/logging/mock.ts
+++ b/src/logging/mock.ts
@@ -7,16 +7,20 @@ import { Event, Logging } from "./logging";
 
 export class MockLogging implements Logging {
   events: Event[] = [];
-  errors: any[] = [];
+  errors: Array<{ message: string; e: unknown }> = [];
   logs: any[] = [];
+  userProperties: Record<string, string> = {};
 
   event(event: Event): void {
     this.events.push(event);
   }
-  error(e: any): void {
-    this.errors.push(e);
+  error(message: string, e: unknown): void {
+    this.errors.push({ message, e });
   }
   log(e: any): void {
     this.logs.push(e);
   }
+  setUserProperty(name: string, value: string): void {
+    this.userProperties[name] = value;
+  }
 }
diff --git a/src/logging/sentry.ts b/src/logging/sentry.ts
new file mode 100644
index 000000000..615a0091a
--- /dev/null
+++ b/src/logging/sentry.ts
@@ -0,0 +1,86 @@
+/**
+ * (c) 2026, Micro:bit Educational Foundation and contributors
+ *
+ * SPDX-License-Identifier: MIT
+ */
+import {
+  addBreadcrumb as sentryAddBreadcrumb,
+  captureException as sentryCaptureException,
+  init as sentryInit,
+} from "@sentry/browser";
+
+/**
+ * Initialise Sentry from build-time env. Returns the configured DSN if
+ * Sentry was set up, or undefined if disabled — callers use that to
+ * short-circuit reporting paths.
+ */
+export const initSentry = (env: Record<string, string>): string | undefined => {
+  const version = env.VITE_VERSION || "unknown";
+  const stage = env.VITE_STAGE || "unknown";
+  // Disable Sentry for the REVIEW stage even if the env var is set.
+  const dsn = stage === "REVIEW" ? undefined : env.VITE_SENTRY_DSN;
+  if (!dsn) {
+    return undefined;
+  }
+  try {
+    sentryInit({
+      dsn,
+      release: `python-editor-v${version}`,
+      environment: stage,
+      ignoreErrors: [
+        // Low consequence and a big chunk of quota.
+        "ResizeObserver loop completed with undelivered notifications",
+      ],
+    });
+  } catch (e) {
+    console.error(e);
+  }
+  return dsn;
+};
+
+/**
+ * Report an error to Sentry (if configured) and the console.
+ */
+export const reportError = (
+  dsn: string | undefined,
+  message: string,
+  e: unknown
+): void => {
+  console.error(message, e);
+  if (!dsn) {
+    return;
+  }
+  try {
+    sentryAddBreadcrumb({
+      message,
+      type: "error-message",
+      level: "error",
+    });
+    sentryCaptureException(e);
+  } catch (err) {
+    console.error(err);
+  }
+};
+
+/**
+ * Add a breadcrumb to Sentry, or console-log it as a fallback when
+ * Sentry isn't configured. Used to record analytics events as context
+ * so they appear in the timeline of any captured exception.
+ */
+export const reportBreadcrumb = (
+  dsn: string | undefined,
+  category: string,
+  data: object | string
+): void => {
+  if (dsn) {
+    sentryAddBreadcrumb({
+      category,
+      message: typeof data === "string" ? data : undefined,
+      data: typeof data === "object" ? data : undefined,
+      level: "info",
+    });
+  } else {
+    // Avoid double-logging via console + Sentry breadcrumbs when Sentry is on.
+    console.log(category, JSON.stringify(data));
+  }
+};
diff --git a/src/logging/sink.ts b/src/logging/sink.ts
new file mode 100644
index 000000000..144312161
--- /dev/null
+++ b/src/logging/sink.ts
@@ -0,0 +1,48 @@
+/**
+ * (c) 2026, Micro:bit Educational Foundation and contributors
+ *
+ * SPDX-License-Identifier: MIT
+ */
+
+export type AnalyticsParams = Record<string, string | number | boolean>;
+
+/**
+ * Output target for analytics events. The Logger owns the cross-cutting
+ * concerns (Sentry, param building, breadcrumbs); the sink owns whatever
+ * is specific to the analytics SDK in use. Same shape as ml-trainer's
+ * sink so a native (Firebase) sink could be dropped in later.
+ */
+export interface AnalyticsSink {
+  event(name: string, params: AnalyticsParams): void;
+  setUserProperty(name: string, value: string): void;
+}
+
+type GtagFn = {
+  (command: "event", eventName: string, params: AnalyticsParams): void;
+  (
+    command: "set",
+    target: "user_properties",
+    values: Record<string, string>
+  ): void;
+};
+
+const gtag = () => (window as Window & { gtag?: GtagFn }).gtag;
+
+/**
+ * Web sink: emits events through gtag when shared-assets/common.js has
+ * set it up. index.html only loads that script for Foundation builds
+ * (VITE_FOUNDATION_BUILD) and the script itself is hostname-gated to
+ * `*.microbit.org`, so OSS forks and local dev take the silent no-gtag
+ * path. Consent is owned by the shared-assets cookie modal, see
+ * src/compliance/web.tsx. GA4 Enhanced Measurement auto-collects
+ * page_view, including the router's pushState navigation.
+ */
+export class WebSink implements AnalyticsSink {
+  event(name: string, params: AnalyticsParams): void {
+    gtag()?.("event", name, params);
+  }
+
+  setUserProperty(name: string, value: string): void {
+    gtag()?.("set", "user_properties", { [name]: value });
+  }
+}
diff --git a/src/logging/stage.ts b/src/logging/stage.ts
new file mode 100644
index 000000000..248f8f6bd
--- /dev/null
+++ b/src/logging/stage.ts
@@ -0,0 +1,15 @@
+/**
+ * (c) 2026, Micro:bit Educational Foundation and contributors
+ *
+ * SPDX-License-Identifier: MIT
+ */
+
+/**
+ * Whether the current build stage routes analytics to a real backend.
+ *
+ * Limited to PRODUCTION and STAGING so REVIEW and local dev don't
+ * pollute the live property with developer / preview traffic. Used by
+ * the web cookie modal config to omit the GA opt-in section.
+ */
+export const isStageWithAnalytics = (stage: string | undefined): boolean =>
+  stage === "PRODUCTION" || stage === "STAGING";
diff --git a/src/project/project-actions.tsx b/src/project/project-actions.tsx
index edfda84b8..958a5f69f 100644
--- a/src/project/project-actions.tsx
+++ b/src/project/project-actions.tsx
@@ -38,6 +38,13 @@ import {
   PythonProject,
 } from "../fs/initial-project";
 import { LanguageServerClient } from "../language-server/client";
+import {
+  AnalyticsTask,
+  deviceFailureCode,
+  importFormat,
+  markUserDisconnect,
+  transport,
+} from "../logging/analytics";
 import { Logging } from "../logging/logging";
 import { SessionSettings } from "../settings/session-settings";
 import { Settings } from "../settings/settings";
@@ -93,6 +100,18 @@ export enum ConnectionAction {
   DISCONNECT = "DISCONNECT",
 }
 
+const analyticsTask = (userAction: ConnectionAction): AnalyticsTask =>
+  userAction === ConnectionAction.FLASH ? "download" : "connect";
+
+const statsParams = (stats: ProjectStatistics) => ({
+  files: stats.files,
+  lines: stats.lines,
+  is_default: stats.defaultMain,
+  storage_used: stats.storageUsed,
+  errors: stats.errorCount,
+  modules: stats.magicModules,
+});
+
 /**
  * Key actions.
  *
@@ -131,17 +150,14 @@ export class ProjectActions {
     userAction: ConnectionAction,
     finalFocusRef: FinalFocusRef
   ): Promise<boolean | undefined> => {
-    this.logging.event({
-      type: "connect",
-    });
-
     const availability = await this.device.checkAvailability();
     if (availability !== "available") {
       this.webusbNotSupportedError(finalFocusRef);
       return false;
     }
 
-    if (await this.showConnectHelp(forceConnectHelp, finalFocusRef)) {
+    const task = analyticsTask(userAction);
+    if (await this.showConnectHelp(forceConnectHelp, task, finalFocusRef)) {
       return this.connectInternal(userAction, finalFocusRef);
     }
   };
@@ -154,6 +170,7 @@ export class ProjectActions {
    */
   private async showConnectHelp(
     force: boolean,
+    task: AnalyticsTask,
     finalFocusRef: FinalFocusRef
   ): Promise<boolean> {
     const showConnectHelpSetting = this.settings.values.showConnectHelp;
@@ -164,6 +181,10 @@ export class ProjectActions {
     ) {
       return true;
     }
+    this.logging.event({
+      type: "device_step",
+      detail: { task, step: "connect_help", transport },
+    });
     const choice = await this.dialogs.show<ConnectHelpChoice>((callback) => (
       <ConnectDialog
         finalFocusRef={finalFocusRef}
@@ -183,6 +204,10 @@ export class ProjectActions {
       case ConnectHelpChoice.Next:
         return true;
       case ConnectHelpChoice.Cancel:
+        this.logging.event({
+          type: "device_exit",
+          detail: { task, at_step: "connect_help", reason: "close", transport },
+        });
         return false;
     }
   }
@@ -194,11 +219,32 @@ export class ProjectActions {
     userAction: ConnectionAction,
     finalFocusRef: FinalFocusRef
   ) {
+    const task = analyticsTask(userAction);
+    this.logging.event({
+      type: "device_step",
+      detail: { task, step: "connecting", transport },
+    });
     try {
       await this.device.connect();
+      if (task === "connect") {
+        // For a download the terminal success is the flash itself.
+        this.logging.event({
+          type: "device_success",
+          detail: { task, transport },
+        });
+      }
       finalFocusRef?.current?.focus();
       return true;
     } catch (e) {
+      this.logging.event({
+        type: "device_failure",
+        detail: {
+          task,
+          at_step: "connecting",
+          code: deviceFailureCode(e),
+          transport,
+        },
+      });
       this.handleWebUSBError(e, userAction, finalFocusRef);
       return false;
     }
@@ -209,12 +255,16 @@ export class ProjectActions {
    */
   disconnect = async (finalFocusRef: FinalFocusRef) => {
     this.logging.event({
-      type: "disconnect",
+      type: "device_disconnect",
+      detail: { reason: "user", transport },
     });
-
+    // Only expect a Connected -> Disconnected status change if we were
+    // actually connected, otherwise the flag would linger.
+    markUserDisconnect(this.device.status === ConnectionStatus.Connected);
     try {
       await this.device.disconnect();
     } catch (e) {
+      markUserDisconnect(false);
       this.handleWebUSBError(e, ConnectionAction.DISCONNECT, finalFocusRef);
     }
   };
@@ -264,14 +314,16 @@ export class ProjectActions {
     files: File[],
     type: LoadType = "file-upload"
   ): Promise<void> => {
-    this.logging.event({
-      type,
-      detail: files,
-    });
-
     if (files.length === 0) {
       throw new Error("Expected to be called with at least one file");
     }
+    this.logging.event({
+      type: "project_import",
+      detail: {
+        source: type === "drop-load" ? "drop" : "file_picker",
+        format: importFormat(files),
+      },
+    });
 
     // Avoid lingering messages related to the previous project.
     // Also makes e2e testing easier.
@@ -389,8 +441,8 @@ export class ProjectActions {
 
   openIdea = async (slug: string | undefined, code: string, title: string) => {
     this.logging.event({
-      type: "idea-open",
-      message: slug,
+      type: "idea_open",
+      detail: { id: slug },
     });
     const pythonProject: PythonProject = {
       files: projectFilesToBase64({
@@ -414,7 +466,7 @@ export class ProjectActions {
 
   reset = async () => {
     this.logging.event({
-      type: "reset-project",
+      type: "project_reset",
     });
     const confirmPrompt = this.intl.formatMessage({
       id: "confirm-replace-reset",
@@ -501,11 +553,6 @@ export class ProjectActions {
       throw new Error("Device connection doesn't support flash");
     }
 
-    this.logging.event({
-      type: "flash",
-      detail: await this.projectStats(),
-    });
-
     if (
       this.device.status === ConnectionStatus.NoAuthorizedDevice ||
       this.device.status === ConnectionStatus.Disconnected
@@ -520,6 +567,13 @@ export class ProjectActions {
       }
     }
 
+    const task: AnalyticsTask = "download";
+    const stats = await this.projectStats();
+    this.logging.event({
+      type: "device_step",
+      detail: { task, step: "flashing", transport },
+    });
+    const flashStart = Date.now();
     const flashingCode = this.intl.formatMessage({ id: "flashing-code" });
     try {
       const firstFlashNotice = (
@@ -544,7 +598,26 @@ export class ProjectActions {
         partial: true,
         progress,
       });
+      this.logging.event({
+        type: "device_success",
+        detail: {
+          task,
+          transport,
+          duration_ms: Date.now() - flashStart,
+          ...statsParams(stats),
+        },
+      });
     } catch (e) {
+      this.logging.event({
+        type: "device_failure",
+        detail: {
+          task,
+          at_step: "flashing",
+          code:
+            e instanceof FlashDataError ? "flash-data" : deviceFailureCode(e),
+          transport,
+        },
+      });
       if (e instanceof FlashDataError) {
         this.actionFeedback.expectedError({
           title: this.intl.formatMessage({ id: "failed-to-build-hex" }),
@@ -567,8 +640,8 @@ export class ProjectActions {
     saveViaWebUsbNotSupported?: boolean
   ) => {
     this.logging.event({
-      type: "save",
-      detail: await this.projectStats(),
+      type: "project_save",
+      detail: { format: "hex", ...statsParams(await this.projectStats()) },
     });
 
     if (!(await this.ensureProjectName(finalFocusRef))) {
@@ -605,7 +678,7 @@ export class ProjectActions {
    */
   saveFile = async (filename: string) => {
     this.logging.event({
-      type: "save-file",
+      type: "file_save",
     });
 
     try {
@@ -627,7 +700,8 @@ export class ProjectActions {
    */
   saveMainFile = async (finalFocusRef: React.RefObject<HTMLButtonElement>) => {
     this.logging.event({
-      type: "save-main-file",
+      type: "project_save",
+      detail: { format: "py", ...statsParams(await this.projectStats()) },
     });
 
     if (!(await this.ensureProjectName(finalFocusRef))) {
@@ -689,7 +763,7 @@ export class ProjectActions {
 
     if (filenameWithoutExtension) {
       this.logging.event({
-        type: "create-file",
+        type: "file_create",
       });
       try {
         const filename = ensurePythonExtension(filenameWithoutExtension);
@@ -714,7 +788,7 @@ export class ProjectActions {
    */
   deleteFile = async (filename: string) => {
     this.logging.event({
-      type: "delete-file",
+      type: "file_delete",
     });
 
     try {
@@ -792,7 +866,7 @@ export class ProjectActions {
    */
   setProjectName = async (name: string) => {
     this.logging.event({
-      type: "set-project-name",
+      type: "project_rename",
     });
 
     return this.fs.setProjectName(name);
diff --git a/src/router-hooks.tsx b/src/router-hooks.tsx
index 88aad796d..f9e7d1dc2 100644
--- a/src/router-hooks.tsx
+++ b/src/router-hooks.tsx
@@ -42,11 +42,10 @@ export interface RouterState {
   focus?: boolean;
 }
 
-type NavigationSource =
-  | "documentation-user"
-  | "documentation-search"
-  | "documentation-from-code"
-  | "documentation-from-simulator";
+/**
+ * How the user reached a documentation page, for the docs_navigate event.
+ */
+export type NavigationSource = "user" | "search" | "code" | "simulator";
 
 type RouterContextValue = [
   RouterState,
@@ -112,11 +111,9 @@ export const RouterProvider = ({ children }: { children: ReactNode }) => {
   const navigate = useCallback(
     (newState: RouterState, source?: NavigationSource) => {
       if (source) {
-        const parts = [newState.tab, newState.slug?.id];
-        const message = parts.filter((x): x is string => !!x).join("-");
         logging.event({
-          type: source,
-          message,
+          type: "docs_navigate",
+          detail: { via: source, surface: newState.tab, id: newState.slug?.id },
         });
       }
       const url = toUrl(newState);
diff --git a/src/serial/SerialBar.tsx b/src/serial/SerialBar.tsx
index ea63ae8d4..75f957620 100644
--- a/src/serial/SerialBar.tsx
+++ b/src/serial/SerialBar.tsx
@@ -47,7 +47,8 @@ const SerialBar = ({
   const logging = useLogging();
   const handleExpandCollapseClick = useCallback(() => {
     logging.event({
-      type: compact ? "serial-expand" : "serial-collapse",
+      type: "serial_toggle",
+      detail: { state: compact ? "expand" : "collapse" },
     });
     onSizeChange(compact ? "open" : "compact");
   }, [compact, onSizeChange, logging]);
@@ -56,7 +57,7 @@ const SerialBar = ({
   const traceback = useDeviceTraceback();
   const syncStatus = useSyncStatus();
   const handleShowHintsAndTips = useCallback(() => {
-    logging.event({ type: "serial-info" });
+    logging.event({ type: "serial_help" });
     setHelpOpen(true);
   }, [logging]);
   const menuButtonRef = useRef<HTMLButtonElement>(null);
diff --git a/src/serial/serial-actions.ts b/src/serial/serial-actions.ts
index c3b6a0e61..d16918d9f 100644
--- a/src/serial/serial-actions.ts
+++ b/src/serial/serial-actions.ts
@@ -19,11 +19,11 @@ export class SerialActions {
   ) {}
 
   interrupt = (): void => {
-    this.logging.event({ type: "serial-interrupt" });
+    this.logging.event({ type: "serial_interrupt" });
     this.sendCommand("\x03");
   };
   reset = (): void => {
-    this.logging.event({ type: "serial-reset" });
+    this.logging.event({ type: "serial_reset" });
     this.sendCommand("\x04");
   };
 
diff --git a/src/simulator/DataLoggingModule.tsx b/src/simulator/DataLoggingModule.tsx
index dc2398d89..ef68d3271 100644
--- a/src/simulator/DataLoggingModule.tsx
+++ b/src/simulator/DataLoggingModule.tsx
@@ -55,7 +55,7 @@ const DataLoggingModule = ({
     });
     saveAs(blob, "simulated-log-data.csv");
     logging.event({
-      type: "sim-user-data-log-saved",
+      type: "sim_log_save",
     });
   }, [logging, untruncatedDataLog]);
   if (minimised) {
diff --git a/src/simulator/SimulatorActionBar.tsx b/src/simulator/SimulatorActionBar.tsx
index 902a2b994..17af16b2e 100644
--- a/src/simulator/SimulatorActionBar.tsx
+++ b/src/simulator/SimulatorActionBar.tsx
@@ -53,7 +53,7 @@ const SimulatorActionBar = ({
       onRunningChange(RunningStatus.STOPPED);
       if (source === "user") {
         logging.event({
-          type: "sim-user-stopped",
+          type: "sim_stop",
         });
       }
     },
diff --git a/src/simulator/SimulatorModules.tsx b/src/simulator/SimulatorModules.tsx
index a05ffb67c..c775b7dad 100644
--- a/src/simulator/SimulatorModules.tsx
+++ b/src/simulator/SimulatorModules.tsx
@@ -175,7 +175,7 @@ const CollapsibleModule = ({
         slug: { id: references[id] },
         focus: true,
       },
-      "documentation-from-simulator"
+      "simulator"
     );
   }, [id, setRouterState]);
   const module = (
diff --git a/src/workbench/SideBarHeader.tsx b/src/workbench/SideBarHeader.tsx
index c8e878729..42752c788 100644
--- a/src/workbench/SideBarHeader.tsx
+++ b/src/workbench/SideBarHeader.tsx
@@ -65,8 +65,8 @@ const SideBarHeader = ({
 
   const handleCollapseBtnClick = useCallback(() => {
     logging.event({
-      type: "sidebar-toggle",
-      message: !sidebarShown ? "open" : "close",
+      type: "sidebar_toggle",
+      detail: { state: !sidebarShown ? "open" : "close" },
     });
     onSidebarToggled();
   }, [logging, onSidebarToggled, sidebarShown]);
@@ -111,7 +111,7 @@ const SideBarHeader = ({
       handleModalClosed();
       // Create new RouterState object to enforce navigation when clicking the same entry twice.
       const routerState: RouterState = JSON.parse(JSON.stringify(navigation));
-      setRouterState(routerState, "documentation-search");
+      setRouterState(routerState, "search");
     },
     [setViewedResults, viewedResults, setRouterState, handleModalClosed]
   );