Keycloak Has a Free API — Add Auth to Any App in Minutes

#keycloak #authentication #api #security

Keycloak is an open-source identity and access management solution. It gives you SSO, OAuth 2.0, OpenID Connect, and user management with a powerful REST API — all for free.

What Is Keycloak?

Keycloak handles authentication so you do not have to build it from scratch. SSO, social login, 2FA, LDAP integration, role-based access — everything you need.

Why Keycloak?

100% free and open-source
Enterprise-grade (Red Hat backed)
REST API for everything
Admin console included
Docker deployment in 1 command

Quick Start with Docker

docker run -p 8080:8080 \
  -e KC_BOOTSTRAP_ADMIN_USERNAME=admin \
  -e KC_BOOTSTRAP_ADMIN_PASSWORD=admin \
  quay.io/keycloak/keycloak:latest start-dev

Admin console: http://localhost:8080

REST API Examples

# Get admin token
TOKEN=$(curl -s -X POST http://localhost:8080/realms/master/protocol/openid-connect/token \
  -d "grant_type=password&client_id=admin-cli&username=admin&password=admin" | jq -r .access_token)

# List users
curl -s http://localhost:8080/admin/realms/master/users \
  -H "Authorization: Bearer $TOKEN" | jq ".[].username"

# Create user
curl -X POST http://localhost:8080/admin/realms/master/users \
  -H "Authorization: Bearer $TOKEN" \
  -H "Content-Type: application/json" \
  -d '{"username":"newuser","enabled":true,"credentials":[{"type":"password","value":"pass123","temporary":false}]}'

Use Cases

Single Sign-On — one login across all your apps
Social login — Google, GitHub, Facebook, Apple
API protection — OAuth 2.0 token validation
User management — CRUD users via API
Multi-tenancy — separate realms per tenant

Node.js Integration

const Keycloak = require("keycloak-connect");
const session = require("express-session");

const keycloak = new Keycloak({ store: new session.MemoryStore() });

app.use(keycloak.middleware());

app.get("/api/protected", keycloak.protect(), (req, res) => {
  res.json({ user: req.kauth.grant.access_token.content.preferred_username });
});

Keycloak vs Alternatives

Feature	Keycloak	Auth0	Firebase Auth
Price	Free	Paid after 7.5K	Paid after 50K
Self-hosted	Yes	No	No
REST API	Full	Full	Limited
Social login	Yes	Yes	Yes
Enterprise features	Yes	Paid	No

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