I got tired of jwt.io having no API, so I shipped one [102ms, Zero Auth]

The problem every dev hits

Testing JWT auth in CI/CD sucks.

jwt.io is perfect but has no API. Auth0's JWT libs need setup. Most online tools rate limit you after 10 requests. You just want to decode or verify a token in a GitHub Action without installing 3 packages.

So I built RK JWT API #003

6 actions. 1 endpoint. 102ms average response.

What it does:

• decode - Instantly decode any JWT. Returns header, payload, expires_in_human
• verify - HS256/384/512 signature validation. Pass secret, get valid: true/false
• verify_jwks - RS256/384/512 via JWKS URL. Works with Auth0, Firebase, Supabase, Okta
• sign - Generate test JWTs. Custom payload, expiresIn. Perfect for mocking auth
• inspect - Security audit. Detects alg:none, expired tokens, clock skew. Returns risk_score
• bulk_decode - Send 100 tokens, get results back. Built for log analysis

Zero friction:

• No API keys
• No signup
• CORS enabled
• Stateless - no logging, no tracking
• Every response includes "by": "RK" so you know it worked

Stack: Vercel Edge Functions + jose. Handles malformed JWTs and edge cases.

Try it right now

Live: https://rapidapi.com/mawmawia/api/rk-jwt-api

Free tier: 1k requests/month. No credit card.

Quick test in cURL:

bash
curl -X POST https://rk-jwt-api.p.rapidapi.com/api \
  -H "X-RapidAPI-Key: YOUR_RAPIDAPI_KEY" \
  -H "Content-Type: application/json" \
  -d '{"action":"decode","token":"eyJhbGciOiJIUzI1NiJ9.eyJzdWIiOiJSUyJ9.signature"}'