Modern Authentication
for Web3 Applications

Bitcoin-based authentication with zero server secrets. Your keys, your identity.

Sign in with any blockchain

How It Works

Simple, secure authentication in three steps

Create Identity

Generate your cryptographic identity locally in your browser

Sign Challenge

Prove ownership by signing a cryptographic challenge

Access Granted

Receive a secure session token for authenticated access

Cross-Device Sync

Backup and restore your identity across all your devices with encrypted cloud sync

Universal Compatibility

Works with any OAuth 2.0 compatible application or service

Access Control

Gate access based on on-chain asset ownership

NFT Gating

Require specific NFT ownership

Token Thresholds

Minimum balance requirements

DAO Membership

Governance token holders only

Time-Based Access

Subscription NFT passes

Multi-Chain Support

Bitcoin, Ethereum, and EVM chains

Verifiable Credentials

Certificates and achievements

Event Ticketing

Admission and attendance proof

Tradeable Access

Resellable NFT subscriptions on open markets

Cloud Backup

Encrypted cloud backup for cross-device access

Cross-Device

Sign in from any device with your password

Zero-Knowledge

Your password encrypts your keys

User Choice

Completely optional feature

Why Choose Sigma Auth?

The most secure, open, and cost-effective authentication solution

Universal

Deploy as a standalone service or embed into existing applications. Works with any framework or platform.

Self-hosted

Runs entirely on your infrastructure. Deploy on Node.js, Bun, AWS Lambda, or Cloudflare Workers.

Standards-based

Implements OAuth 2.0 spec and web standards. Any OAuth client can use it.

Access Control

Verify NFT ownership and token holdings with on-chain cryptographic proof.

Cross Device Restore

Restore your identity across all your devices with just your password.

Backup File Import

Handles all backup file formats. Import your backup file to sign in.

On-Chain Profiles

Supports BAP profiles automatically when you sign in with associated keys.

For Developers

Use our public OAuth 2.0 API, or host your own

Quick Start

1

Redirect to authorization endpoint

Point users to /login with your client_id and redirect_uri

2

User completes Bitcoin authentication

Users sign with Bitcoin keys or restore from backup, returns authorization code

3

Exchange code for JWT access token

POST to /token endpoint with authorization code

4

Use token for authenticated API calls

Include Bearer token in Authorization header

API Endpoints

OAuth 2.0 Core

GET/login
POST/token
GET/userinfo

Authentication

POST/loginBitcoin
GET/google/callbackGoogle
GET/github/callbackGitHub

Backup & Restore

GET/backup
POST/backup
GET/backup/status
GET/backup/oauth
POST/backup/link-oauth

Wallet & Subscription

POST/api/wallet/connect
GET/api/wallet/address
GET/api/wallet/nfts
POST/api/wallet/verify-ownership
GET/api/subscription/status

One-Click Deploy

Deploy to Vercel (managed) or Dokploy (self-hosted VPS)