JWT Decoder
JWT Decoder
About JWT Decoder
Decode JWT tokens online with our free JWT decoder and JWT parser. Inspect the header, payload, and signature of any JSON Web Token. Paste a JWT to view its claims, expiration, issuer, and more — ideal for debugging authentication, inspecting token claims, and verifying expiration. No secret key required.
Example
JWT Structure
header.payload.signatureDecoded Output
Header: { "alg": "HS256", "typ": "JWT" }
Payload: { "sub": "user123", "exp": 1234567890 }Why Use JWT Decoder?
- Debug authentication — Inspect JWTs from login flows, APIs, and OAuth to troubleshoot auth issues.
- Inspect token claims — View sub, exp, iss, aud, and custom claims without writing code.
- Verify expiration — Check exp and nbf claims to ensure tokens are valid and not expired.
JWT Decoder FAQs
What is a JWT?
A JSON Web Token (JWT) is a compact, URL-safe token format used for authentication and information exchange. It consists of three Base64-encoded parts: header, payload, and signature.
Does this tool verify JWT signatures?
No. This tool only decodes and displays the header and payload. Signature verification requires the secret key or public key used to sign the token.
Is it safe to paste JWTs into online tools?
JWTs often contain sensitive data like user IDs and permissions. This tool runs entirely in your browser — no data is sent to any server. However, avoid pasting production tokens with real secrets into any online tool.
Is it safe to decode JWTs in the browser?
Yes. JWTs are not encrypted by default — they are Base64-encoded. Decoding reveals the claims but does not compromise security. The signature still protects integrity.
What are common JWT claims?
Standard claims include iss (issuer), exp (expiration), sub (subject), aud (audience), iat (issued at), and nbf (not before).