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Using AWS Cognito for Application Authentication

Learn how to use AWS Cognito as your application's serverless identity provider.

Overview​

AWS Cognito is a managed identity service that provides serverless authentication, user management, and OIDC token issuance.

Coming Soon​

This guide is under development. Topics will include:

  • Creating Cognito User Pools
  • Configuring app clients
  • Integrating with API Gateway
  • Validating Cognito tokens
  • Custom attributes and claims
  • Social identity providers
  • Lambda triggers for customization
  • Federated identities

Use Cases​

1. Serverless Applications​

Authenticate users in serverless architectures:

  • Lambda function authorization
  • API Gateway integration
  • No infrastructure to manage
  • Pay-per-use pricing

2. Mobile Applications​

Native authentication for mobile apps:

  • iOS/Android SDKs
  • Social login support
  • Secure token storage
  • Offline access

3. Federated Authentication​

Connect multiple identity sources:

  • Social providers (Google, Facebook)
  • SAML identity providers
  • OpenID Connect providers
  • Custom authentication flows

Quick Example​

// Verify Cognito token in Lambda
const jwt = require('jsonwebtoken');
const jwksClient = require('jwks-rsa');

const region = 'us-east-1';
const userPoolId = 'us-east-1_XXXXX';

const client = jwksClient({
  jwksUri: `https://cognito-idp.${region}.amazonaws.com/${userPoolId}/.well-known/jwks.json`
});

function getKey(header, callback) {
  client.getSigningKey(header.kid, (err, key) => {
    callback(null, key.publicKey || key.rsaPublicKey);
  });
}

exports.handler = async (event) => {
  const token = event.headers.Authorization.replace('Bearer ', '');

  return new Promise((resolve, reject) => {
    jwt.verify(token, getKey, {
      issuer: `https://cognito-idp.${region}.amazonaws.com/${userPoolId}`,
      algorithms: ['RS256']
    }, (err, decoded) => {
      if (err) return reject(err);
      resolve(decoded);
    });
  });
};

Resources​

Contributing​

Want to help complete this guide? Contribute on GitHub.