JWT Decoder
Decode and inspect JWT tokens instantly in your browser
Encoded JWT Token
Awaiting JWT Token
Enter a valid JSON Web Token on the left to start decoding, inspecting claims, and analyzing security properties in real-time.
JSON Web Token Guide
Learn how JWT authentication works, standard claims, and security considerations
How to Use the JWT Decoder
- 1Input Encoded Token
Paste your full Base64-encoded JWT token into the text area. You can also drag and drop a token file, upload it, or load a sample token.
- 2Inspect Real-Time Output
As you type or paste, the tool immediately decodes the token into three distinct tabs: Header (metadata), Payload (claims), and Signature verification.
- 3Explore Security Risks
Check the automated Risk Assessment cards for critical issues like expired status, weak algorithms (HMAC/none), or missing standard claims (exp, iss, iat).
- 4Search & Copy Claims
Use the searchable Claims Explorer to search for specific claims like roles or sub-claims, copy individual values, and view description details of standard claims.
Quick JWT Facts
Frequently Asked Questions
What is a JWT Decoder?
A JWT Decoder allows you to inspect the header, payload claims, and signature structure of a JSON Web Token.
Can I verify JWT signatures here?
This tool decodes and displays token details. It does not verify signatures as that requires the original signing secret or public keys.
Is JWT decoding safe on this site?
Yes. Decoding is handled entirely client-side using JavaScript in your browser. Your token is never uploaded.
What information is stored in a JWT?
JWTs contain user claims, expiration time, issuer details, role-based authorization parameters, and signature algorithms.
Can I decode expired JWT tokens?
Yes. Expired tokens can still be parsed to inspect their claims, payload properties, and header configurations.
What does a JWT signature do?
The signature allows verification that the token has not been altered or tampered with since creation.
Can I modify token payloads and re-sign them?
This is a decoder tool only. Re-signing requires the private key or secret, which should not be exposed online.
Why is my JWT token not decoding?
Ensure you have pasted the complete three-part token separated by dots. Missing characters or invalid base64url characters will break decoding.