JWT Decoder
Updated on:Decode JWT (JSON Web Token) tokens online for free.
How it works
1. Paste the JWT token. 2. Click Decode. 3. View header, payload and expiration.
Advantages
Instant decoding. Expiration display. Groups and claims. No data sent to external servers.
Common mistakes to avoid
- Decoding ≠ verification: this tool decodes the JWT but does not verify its signature. A decoded token might have been tampered with.
- Expired token: always check the "exp" (expiration) field. An expired token is still decodable but should not be accepted.
- Don't share sensitive JWTs: JWTs contain information (claims) that anyone can read. Don't paste them in online tools you don't trust.
- Algorithm confusion: make sure the server verifies the algorithm in the header. Accepting "none" as algorithm is a critical vulnerability.
Description
Free Online JWT Decoder
Our JWT decoder (JSON Web Token) analyzes and decodes JWT tokens showing header, payload and signature. JWTs are widely used for authentication and authorization in modern web applications, REST APIs and microservice architectures.
JWT Structure
- Header: Algorithm and token type
- Payload: Claims and user data
- Signature: Cryptographic signature
Uses
Authentication debugging, claims inspection, secure API development, session troubleshooting.
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Category
Web/Dev ToolsSommario