01 overview

01 — Overview

Simple Launcher — an open-source emulator frontend for Windows (x64 & ARM64). Related: 02 — Projects & Solution · 03 — Quickstart · README (docs index)

What it is

Simple Launcher is a WPF desktop application that organizes, browses, and launches a retro (and modern PC) game collection through emulators. It is a frontend: it does not ship ROMs, ISOs, or BIOS files, and you must provide your own emulators.

Three code projects implement it:

Project	Role
SimpleLauncher (WPF app)	The launcher itself: windows, pages, ViewModels, UI services, launch handlers, game scanners, DI composition root
SimpleLauncher.Core (class library)	Platform-independent services, models, interfaces, data persistence, emulator config injection
SimpleLauncher.Avalonia (Avalonia UI app)	Cross-platform port (Windows + Linux) reusing all of Core; port status tracked in AvaloniaPlan.md

Key differentiators

• Configuration injection into 21 emulators — Ares, Azahar, Blastem, Cemu, Daphne, Dolphin, DuckStation, Flycast, MAME, Mednafen, Mesen, PCSX2, Raine, Redream, RetroArch, RPCS3, Sega Model 2, Stella, Supermodel, Xenia, Yumir. Settings are written into each emulator's own config file before launch (see 06 — Systems & Launch).
• Universal CHD support — the bundled CHDMounter mounts CHD files as virtual drives for 15+ emulators without native CHD support (Xenia, RPCS3, Xemu, Cxbx-Reloaded, Mednafen, Mesen, Raine, FinalBurn Neo/Alpha, 4DO, Gens, Blastem, Yabause, PCSX-Redux, CD-i Emulator, Tsugaru, Kega Fusion, DOSBox).
• On-the-fly mounting — launch games directly from .zip, .iso, .xiso, .chd without manual extraction (requires Dokan).
• Modern store integration — automatic scanning for games from Steam, Epic, GOG, Microsoft Store, Amazon, Battle.net, EA App, Humble, itch.io, Rockstar, Uplay (see 10 — Game Scanning).
• RetroAchievements integration — login, per-game achievements/rankings, profile, completion progress, hashing for complex systems, and automatic credential injection into supported emulators (see 09 — RetroAchievements).
• Easy Mode wizard — guided download & configuration of emulators, cores, and image packs.
• Expert Mode — full manual control of system.xml: multiple ROM folders, placeholders (%BASEFOLDER%, %SYSTEMFOLDER%, %EMULATORFOLDER%, %ROM%, %NAME%, %ROMSYSTEMFOLDER%), launch parameters.
• Performance — MessagePack binary storage (favorites.dat, playhistory.dat, history.dat, mame.dat, RetroAchievements.dat), async scanning/loading, pagination.
• Platform coverage — native x64 and ARM64 builds; Windows 10+; .NET 10 runtime.

Feature surface (summary)

• Dual Grid / List views, letter filter bar, system selection screen, pagination, zoom, aspect ratios, filename display modes.
• Favorites, Play History (play count, play time, last played), Global Search with AND/OR, Global Statistics.
• Fuzzy cover-image matching with configurable threshold + annotation stripping (Game (USA) → Game).
• Themes (Light, Dark, Adaptive, High Contrast, Midnight) + 27 accent colors; 18 languages (ar, bn, de, en, es, fr, hi, id, it, ja, ko, nl, pt-br, ru, tr, ur, vi, zh-hans).
• Gamepad navigation (Xbox XInput + PlayStation DirectInput), dead-zone configuration, UI sound effects (NAudio).
• Tray icon, minimize-to-tray, F8 global screenshot hotkey, loading overlays, status bar, debug window (-debug).
• Built-in updater (Updater.exe) with GitHub release assets, --restarting restart flow.
• Bundled power tools — conversion (CHD, RVZ, XISO, 7z/zip), batch-file creators, cover tools, ROM validator (see 11 — Bundled Tools).
• 100+ supported systems — Nintendo, Sony, Sega, Atari, NEC, SNK, Commodore, arcade (MAME/FBN/Raine), retro computers, and modern PC storefronts (the authoritative per-system emulator guide is parameters.md; see also 18 — Emulator Parameters).

Localization

18 languages ship as one shared set of JSON packs: SimpleLauncher.Core\Localization\strings.{code}.json (2669 keys per file, UTF-8 without BOM, key-sorted). Both apps embed them in their assemblies — Avalonia as manifest resources (SimpleLauncher.Avalonia.Resources.strings.{code}.json, loaded by LocalizationService) and WPF as pack resources (resources/strings.{code}.json in SimpleLauncher.g.resources, with App.ApplyLanguage building the WPF ResourceDictionary from the JSON). Switching language restarts the app. See 08 — UI Layer.

SimpleLauncher.ResourceTranslator (OpenRouter API, default z-ai/glm-5.3-flash) propagates missing keys from strings.en.json to all other languages; see its README.

Version & license

• Current version: 5.8.0 (SimpleLauncher.csproj is canonical; SimpleLauncher.Core.csproj and both app.manifest files are kept in sync and covered by VersionConsistencyTests). The Avalonia app (SimpleLauncher.Avalonia) is synced to the same version (5.8.0) and ships in the same release bundle.
• The secondary server publishes a version.txt (e.g. release5.8.0) used by the update-check fallback.
• Framework: .NET 10 (net10.0-windows), C# 14, nullable reference types enabled.
• License: GPLv3 (LICENSE.txt).
• Repository: https://github.com/purelogiccode/SimpleLauncher

Release history

See 17 — Release Notes for a condensed changelog (5.8.0 → 1.1); the canonical file is SimpleLauncher\WhatsNew.md.

Related docs

• Docs index
• 02 — Projects & Solution
• 04 — Architecture