Why Use This Tool
Understanding JWT structure requires seeing how headers and payloads become tokens. An encoder shows the encoding process and produces tokens for testing authentication systems.
JWT Encoder
Free online JWT encoder. Create and sign JSON Web Tokens (JWT) with HS256, HS384, or HS512 directly in your browser. — runs 100% in your browser, client-side only. No data is sent to any server. Free to use, no account required.
Free
Client-Side
No Login
No Storage
Loading tool...
How to Use the JWT Encoder
- Enter a JSON payload with your claims.
- Choose an algorithm (HS256/384/512).
- Enter a secret key for HMAC signing.
- Click Create JWT to generate the token.
Uses the Web Crypto API for HMAC signing. Your secret never leaves the browser. For RS256/ES256, use a library like jose.js.
What is JWT Encoder?
A JWT encoder takes header and payload JSON, encodes them to Base64URL, and creates a valid JWT structure. With a secret key, it also generates the signature for a complete, signed token.
When to Use It
Use JWT encoding when learning JWT structure, creating test tokens, debugging encoding issues, or generating tokens from custom header/payload combinations.
Common Uses
- Learning JWT structure
- Creating test tokens
- Debugging JWT encoding
Frequently Asked Questions
What's Base64URL encoding?
Like Base64 but URL-safe: + becomes -, / becomes _, and padding (=) is removed. This ensures JWTs are safe in URLs without percent-encoding.
Can I create unsigned JWTs?
Technically yes (alg: none), but unsigned JWTs are insecure and rejected by most systems. Always sign JWTs with a secret or key pair.
How do I verify my generated JWT?
Use CipherKit's JWT decoder to parse the token and verify the structure. For signature verification, use the same key and algorithm used for signing.