Decode a JSON Web Token (JWT) to instantly view its header and payload in a readable JSON format. JWT decoding does not require a secret key because the token data is Base64URL encoded, not encrypted.
This JWT Decoder runs entirely in your browser and does not send any data to a server. It is useful for inspecting claims, debugging authentication issues, and understanding token structure during development.
100% Client-Side Execution. No Data Sent to Server Secure
Decode a JSON Web Token to instantly view its header and payload. No secret or private key is required.
Validate a JWT by verifying its signature and checking registered claims such as expiration and not-before.
Generate a signed JWT using custom headers and claims for testing authentication and authorization flows.
All processing happens locally using the browser’s WebCrypto API. Your tokens and keys are never sent to any server, making this tool safe for debugging production JWTs.
A JSON Web Token (JWT) is a compact, URL-safe means of representing claims to be transferred between two parties. It consists of three parts: Header, Payload (claims), and Signature.
JWTs are widely used for API authentication, single sign-on (SSO), and securely transmitting information between client and server. Learn more at JWT.io and Auth0's JWT guide. You can also follow this tutorial to implement the JWT based auth mechanism in spring boot.
A JWT consists of three parts separated by dots: the header, the payload, and the signature. While the signature ensures integrity, the header and payload can be decoded without verification.
JWT decoding converts the Base64URL-encoded header and payload into readable JSON. This allows developers to inspect token metadata and registered claims such as issuer, subject, and expiration time.
Decoding does not verify token authenticity. To ensure a token has not been tampered with, signature verification should be performed using a JWT validator.
JWT decoding is safe when performed in a trusted environment. This tool processes tokens entirely in your browser and does not transmit any data externally.
For cryptographic validation, combine decoding with signature verification and encryption tools such as RSA encryption or ECC key verification.
A JWT decoder is a tool that converts a JSON Web Token into a readable JSON format by decoding its header and payload.
Yes. Decoding a JWT does not require a secret key because the token is encoded, not encrypted.
No. Decoding only reveals the token contents. Signature verification and claim checks are required to validate authenticity.
It is safe if decoding is done locally. This JWT Decoder runs entirely in the browser and does not send data to any server.
You can view the token header, payload claims such as issuer and expiration, and the algorithm used to sign the token.
A JWT Decoder is commonly used during development and debugging to inspect the contents of a token without performing cryptographic verification.
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