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OAuth 2.1 · OpenID Connect · Bitcoin identity

Sign in with a key,
not a password.

Sigma Auth is an authorization server where people and AI agents prove who they are with a Bitcoin identity key. Keys stay on the device. The server only verifies signatures.

Create an identitySign inRead the docs
People

Your key, on your device

Create a Bitcoin identity in the browser, unlock it with a password or passkey, and approve sign-ins from any device.

Create an identity
Applications

Standard OAuth, nothing exotic

Authorization code with PKCE and OpenID Connect out of the box, or drop the Better Auth plugin into an existing project.

Integration guide
Agents

Headless by design

Register clients programmatically, authenticate with Bitcoin-signed requests, and request short-lived scoped capabilities.

Agent portal