JWT Decoder
Paste any JWT and instantly see the decoded header, payload, and claims
Paste any JWT token and instantly see the decoded header, payload claims, and signature. Inspect expiry times, user IDs, permissions, and any custom claims — without needing to write code.
What Is a JWT?
A JSON Web Token (JWT) is a compact, URL-safe token used for authentication and authorisation. It consists of three Base64-encoded parts separated by dots:
header.payload.signature- Header — algorithm and token type
- Payload — claims (user ID, roles, expiry, etc.)
- Signature — cryptographic proof the token wasn't tampered with
How to Read JWT Claims
Common standard claims (iss, sub, aud, exp, iat) plus custom claims from your identity provider:
| Claim | Meaning |
|---|---|
sub |
Subject (usually user ID) |
iss |
Issuer (who created the token) |
exp |
Expiry timestamp (Unix epoch) |
iat |
Issued at timestamp |
aud |
Audience (intended recipient) |
Security Note
This decoder runs entirely in your browser — no token data is sent to any server. That said, never paste production JWT tokens into untrusted online tools. Use this for debugging only.
JWT in APIs and Automations
If you're building API integrations or automation workflows that use Bearer token authentication, this tool helps you inspect tokens to debug auth failures, check expiry, and verify claims. API Automation for Businesses covers Bearer token auth in the broader context of connecting business APIs, and the Base64 Encoder/Decoder is useful if you need to inspect the raw encoded segments manually.
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