evm-vanity

Grind an EVM address that starts or ends with characters you choose, in your browser, across every core, with an honest account of what it costs.

Try it without installing anything: npx wrangler deploy --temporary puts this whole thing (site, API and discovery documents) on a Cloudflare Workers URL in about thirty seconds and needs no account, no token and no configuration. That preview is disposable and gets a fresh subdomain every time; npx wrangler deploy with a Workers-scoped token puts it somewhere permanent.

A complete vanity wallet stack for Ethereum, Base, Arbitrum, Robinhood Chain and every other EVM network: the browser grinder, the site, an HTTP API, a CLI, an MCP server for AI assistants, EIP-712 provenance attestations a contract can verify, and a delegation protocol that lets somebody else do the work without ever being able to compute your key.

npx evm-vanity grind --prefix beef --keystore wallet.json

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Why another vanity generator

1. Entropy, which is the only thing that has ever mattered here

In 2022 the most popular EVM vanity generator seeded its search from a 32-bit value. Every key it had ever produced became searchable and tens of millions of dollars were drained. This grinder draws a full 256-bit base scalar from the platform CSPRNG, re-seeds every million candidates so no run extends one arithmetic progression indefinitely, and re-derives every match through a separate code path before emitting it. A key that does not control the address it matched is never returned; there is a test for that.

2. Numbers that are not folklore

Every nibble of an EVM address is uniform, so 0x0000… is exactly as hard as 0xdead… and a suffix costs the same as a prefix. The number tools do get wrong is casing: EIP-55 re-cases hex letters with keccak bits, so asking for a specific spelling costs 2x per letter. dEaD is sixteen times harder than any-case dead, and this project says so in every quote.

Grinding is geometric, so the mean is not a deadline. Quotes report p50, p90 and p99 next to the expected value, because the tail is what a decision to start actually depends on.

3. Delegation with no downside at all

Hard patterns need more compute than a browser tab has, and handing the job to someone else normally means handing over the key. Split-key grinding removes that trade with group arithmetic on secp256k1:

1. you pick a secret scalar k1 locally and publish only P1 = k1·G;
2. the grinder searches offsets k2 where the address of P1 + k2·G matches;
3. it returns k2, which is useless without k1;
4. you combine k = (k1 + k2) mod n on your own machine.

npx evm-vanity delegate --prefix beef

Private keys on secp256k1 are scalars, so the combined result is an ordinary 32-byte key that imports into MetaMask, ethers, viem, Rabby or a keystore file like any other. (The Ed25519 version of this trick, on Solana, yields an expanded key that seed-only wallets reject. Not here.) The attestation publishes k2·G, so anyone can check address(P1 + k2·G) == address and confirm non-custody from public values alone.

4. Provenance a contract can check

Attestations are EIP-712 typed data, not opaque blobs, so a marketplace, a registry or an escrow recovers the signer with ecrecover in three lines of Solidity and can refuse to list an address that is not provably ground and never custodied. The same document verifies off chain, in the browser, with no RPC.

npx evm-vanity verify attestation.json

The exact type hash and domain separator are served at /.well-known/evm-vanity.json so a deployed verifier and this library cannot drift apart. The domain carries no chainId on purpose: an attestation is a statement about an address, and an address is the same on every EVM chain.

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Install and run

git clone https://github.com/nirholas/evm-vanity
cd evm-vanity
npm install
npm run dev            # site on http://localhost:5181, API on http://localhost:8788
npm test               # 52 tests

Production:

npm run build
ATTESTATION_KEY=<32-byte hex> npm start      # one process serves site + API

Cloudflare Workers, Docker, Cloud Run: see docs/deploy.md.

Install the CLI and library from npm:

npm install evm-vanity

import { addressFromPrivateKey, inspectAddress, splitKey } from 'evm-vanity';

const address = addressFromPrivateKey(privateKey);
const details = inspectAddress(address);
const requester = splitKey.generateRequesterShare();

The package root exports address helpers directly. Split-key, attestation, chain, difficulty and validation helpers are available as namespaces; the existing documented subpath imports remain supported.

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One key, every chain

An EVM address is keccak256(pubkey)[12:]. It does not depend on a network, so a single grind gives you the same address on Ethereum, Base, Arbitrum, Robinhood Chain, OP, Polygon, BNB and Avalanche at once, and on chains that do not exist yet.

The registry in src/chains.js exists for explorer links and for the deterministic CREATE2 deployers, which matter only if you later want a contract at a vanity address. Every row was verified with eth_getCode against the listed public RPC, and both the chains page and evm-vanity chains --verify re-run that check, so the table can be re-verified rather than trusted.

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The pieces

Surface	Where	What it is
Browser grinder	index.html, src/ui/app.js	One Web Worker per core. Live rate, pause/resume, encrypted keystore export.
Delegation	delegate.html	The split-key protocol, end to end, in the tab.
Chains	chains.html	The registry, re-verified against live RPCs from your browser.
Verifier	verify.html	Attestation verification, entirely client-side, with the Solidity to do it on chain.
Grind loop	src/eoa-grinder-worker.js	Incremental point addition, full-entropy seeding, per-match self-check.
Difficulty	src/difficulty.js	The uniform-nibble model and the EIP-55 case multiplier.
Split-key	src/split-key.js	The non-custodial delegation protocol.
Attestations	src/attestation.js	EIP-712 issue and verify, with the type hash a contract needs.
HTTP API	server/	One Fetch handler, hosted on Node or Cloudflare, identical on both.
CLI	cli/evm-vanity.js	grind, delegate, quote, inspect, verify, chains, serve, mcp.
MCP server	mcp/index.js	Six tools for AI assistants.

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CLI

evm-vanity grind --prefix beef --suffix dead --keystore wallet.json
evm-vanity grind --prefix BeeF                 # EIP-55 spelling, 16x harder
evm-vanity delegate --prefix beef              # split-key, nothing leaks
evm-vanity quote --prefix dEaD --rate 17000
evm-vanity inspect 0xdEaD…
evm-vanity verify attestation.json
evm-vanity chains --verify
evm-vanity serve --port 8788
evm-vanity mcp

Add --json to anything for machine-readable output.

MCP

{
  "mcpServers": {
    "evm-vanity": { "command": "npx", "args": ["-y", "evm-vanity", "mcp"] }
  }
}

Tool	Does
vanity_quote	Difficulty, rarity, ETA, and the EIP-55 case multiplier.
vanity_grind	Grind a real keypair locally, across every core.
vanity_split_key_grind	Delegate a hard pattern without exposing a key.
vanity_inspect_address	Validate, checksum and score an address.
vanity_verify_attestation	Verify an attestation offline.
vanity_chains	Chains and the deployers live on each.

HTTP API

Full schema at /openapi.json; agent card at /.well-known/agents.json.

curl -s http://localhost:8788/api/quote \
  -H 'content-type: application/json' \
  -d '{"prefix":"dEaD","attemptsPerSecond":17000}'

Endpoint	Does
POST /api/quote	Probability, expected attempts, p50/p90/p99, rarity, case multiplier.
POST /api/inspect	Validate an address, check its checksum, score its pattern.
GET /api/chains	The chain and deployer registry.
POST /api/attest	Sign an EIP-712 attestation.
POST /api/verify	Verify one.
POST /api/splitkey/grind	Non-custodial delegated grinding.
POST /api/splitkey/verify	Check a split-key claim.
POST /api/grind	Custodial server-side grind. Disabled by default.

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Documentation

Document	Covers
docs/difficulty-model.md	The uniform-nibble model, EIP-55 casing, and why the mean is not a deadline.
docs/protocol-split-key.md	The delegation protocol and its wire format.
docs/protocol-attestation.md	The EIP-712 format, every verifier check, and the Solidity to check it on chain.
docs/deploy.md	Node, Docker, Cloud Run, Cloudflare Workers, static-only.
docs/discoverability.md	The documents crawlers, assistants and agent runtimes read, and where to submit the project.
SECURITY.md	What this project promises, and what it does not.
CONTRIBUTING.md	Running it and the quality bar.

The site also ships its own documentation page at /docs.html.

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Security model

Path	Who can see the key
Browser grinder	Only your browser. No request carries key material.
CLI grind	Only your machine.
CLI / API delegate	Only you. The remote side holds an offset that is useless without your k1.
POST /api/grind	The server process and every hop in between. Off unless an operator sets ALLOW_SERVER_GRIND=1.

Report vulnerabilities through GitHub security advisories. See SECURITY.md.

Environment

Variable	Meaning
ATTESTATION_KEY	32-byte secp256k1 key (hex) for signing attestations. Unset means an ephemeral per-process key, reported in every response. Mint one with npm run keygen. It is a signing identity, not a wallet: do not fund it.
ALLOW_SERVER_GRIND	1 enables the custodial grind endpoint. Off by default.
PORT	Node listen port. Default 8788.
EVM_VANITY_API	Default remote API for delegate and verify.

Provenance

The browser grinder, its worker, the pattern validation and the hex wordlist were first built inside three.ws and are re-licensed here under Apache-2.0. The secp256k1 split-key protocol, the EIP-712 attestation format, the chain registry, the API, the CLI and the MCP server are new in this repository.

Licence

Apache-2.0. See NOTICE for attribution.