JWT Decoder
Decode and analyze JSON Web Tokens (JWT) online
Header
Payload
Signature
The signature cannot be decoded as it contains the cryptographic hash of the header and payload.
Token Information
How JWT Decoder Works
What is a JWT?
JSON Web Token (JWT) is an open standard (RFC 7519) that defines a compact and self-contained way for securely transmitting information between parties as a JSON object. JWTs are commonly used for authentication and authorization in web applications.
JWT Structure
A JWT consists of three parts separated by dots (.) :
- Header: Contains metadata about the token (algorithm, type)
- Payload: Contains the claims (user data, expiration, etc.)
- Signature: Cryptographic signature to verify token authenticity
Security Note
Important: Never paste sensitive JWT tokens containing real user data or secrets into online tools. This tool only decodes the header and payload - the signature remains encrypted and secure.
Frequently Asked Questions
What is JWT decoding?
JWT decoding refers to the process of extracting and viewing the header and payload portions of a JSON Web Token. The signature cannot be decoded as it contains cryptographic hash data.
Is it safe to decode JWT tokens online?
Yes, for development and debugging purposes. However, never use this tool with production tokens containing sensitive user data. The signature portion remains secure and cannot be decoded.
What information can I see in a decoded JWT?
You can view the header (algorithm and token type), payload (user claims, expiration time, issued time), and signature. Common claims include user ID, roles, permissions, and timestamps.
Can I verify JWT signatures with this tool?
No, this tool only decodes the visible portions of the JWT. Signature verification requires the original secret key used to sign the token, which should never be shared online.
What are common JWT use cases?
JWTs are commonly used for API authentication, single sign-on (SSO), session management, and secure data transmission between services in microservice architectures.