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JWT Debugger

Decode, verify, and encode JWT tokens with support for all major signing algorithms

🔌Debug JWTs via MCP in VS Code, Claude & AI Assistants

JWT Token

Paste your JWT token here

Decoded JWT

Enter a valid JWT to see decoded content

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Enter a JWT token to see the decoded content

Supported Algorithms

HMAC

HS256
HMAC using SHA-256
HS384
HMAC using SHA-384
HS512
HMAC using SHA-512

RSA

RS256
RSASSA-PKCS1-v1_5 using SHA-256
RS384
RSASSA-PKCS1-v1_5 using SHA-384
RS512
RSASSA-PKCS1-v1_5 using SHA-512

ECDSA

ES256
ECDSA using P-256 and SHA-256
ES384
ECDSA using P-384 and SHA-384
ES512
ECDSA using P-521 and SHA-512

What is a JWT?

A JSON Web Token (JWT) is a compact, URL-safe means of representing claims to be transferred between two parties. It is commonly used for authentication and authorization in web applications. A JWT consists of three parts: a header, a payload, and a signature.

How to use our JWT Debugger

  1. Paste your JWT token into the input field to decode it.
  2. The header and payload will be displayed in a readable format.
  3. To verify the signature, enter your secret key and click "Verify Signature".
  4. To encode a new token, switch to "Encode" mode, fill in the header and payload, provide a secret key, and click "Encode Token".

Features of our JWT Debugger

  • Decode & Encode: Easily switch between decoding existing tokens and encoding new ones.
  • Signature Verification: Verify the integrity of your JWTs with your secret key.
  • Algorithm Support: Supports all major signing algorithms, including HMAC, RSA, and ECDSA.
  • Claim Explanations: Understand the meaning of standard JWT claims.

Frequently Asked Questions (FAQ)

What is the difference between the header, payload, and signature?

The header contains metadata about the token, the payload contains the claims (the data), and the signature is used to verify that the token has not been tampered with.

Is it safe to use this tool with my production JWTs?

Yes, all processing is done on the client-side in your browser. No data, including your tokens and secret keys, is ever sent to our servers.

What is a "claim" in a JWT?

A claim is a piece of information asserted about a subject. For example, a claim could be the user's name or their permissions.

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