Open-source browser extension

MetaMask for AI.

A secure browser wallet for your LLM API keys and auth tokens. Connect to any app — your keys never leave the extension.

How it works

Install the wallet

Add the byoky extension to Chrome, Firefox, or Safari. Set a master password to encrypt your vault.

Add your keys

Paste API keys or sign in with OAuth. Everything is encrypted locally with AES-256-GCM. Multiple keys per provider.

Connect to any app

Visit any byoky-enabled app. Approve access in one click. Your keys stay in the vault — always.

Integrate in minutes.

Use your favorite provider SDK with byoky's fetch proxy. Two extra lines. Full API compatibility. Keys never touch your app.

npm install @byoky/sdk

Native SDK compatibility

Works with the official Anthropic, OpenAI, and Gemini SDKs. Just swap in byoky's fetch.

Streaming out of the box

Full SSE streaming support through the extension proxy. No special handling needed.

Provider discovery

Detect which providers the user has. Request specific providers or accept any available one.

app.ts
import Anthropic from '@anthropic-ai/sdk';
import { Byoky } from '@byoky/sdk';

const byoky = new Byoky();
const session = await byoky.connect({
  providers: [{ id: 'anthropic', required: true }]
});

// Use the native Anthropic SDK — keys never exposed
const client = new Anthropic({
  apiKey: session.sessionKey,
  fetch: session.createFetch('anthropic'),
});

Built for paranoia.

Security isn't a feature — it's the entire point.

AES-256-GCM encryption

Keys are encrypted with a password-derived key using PBKDF2 with 600,000 iterations. Web Crypto API — no dependencies.

Zero key exposure

API keys never leave the extension process. Apps receive temporary session tokens. The extension proxies every request.

Full audit log

Every API request is logged with the app origin, provider, status, and timestamp. Complete visibility into credential usage.

Local only

No cloud. No telemetry. No tracking. Everything is stored on your device, encrypted behind your master password.

Your providers.

Bring credentials from any supported provider.

Anthropic
API Key + OAuth
OpenAI
API Key
Google Gemini
API Key

More providers coming. Or add any provider with a custom API key.

Built in the open.

byoky is fully open source under the MIT license. Audit the code, contribute, or fork it.

Star on GitHub

MIT License — free forever.