Axonix Tools
Client-Side Decoder

JWT Debugger

Decode, verify and debug JSON Web Tokens. Paste your token to view its header and payload instantly.

Encoded Token

Header

Algorithm & Token Type

{}

Payload

Data & Claims

{}

Signature

Verified Signature

HMACSHA256(
  base64UrlEncode(header) + "." +
  base64UrlEncode(payload),
  your-256-bit-secret
)

Before You Start

Axonix JWT Debugger is a fast, privacy-first utility that runs directly in your browser. Get started in seconds: Paste your JSON Web Token (JWT) into the input field on the left.

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How to Use JWT Debugger
  • 1Paste your JSON Web Token (JWT) into the input field on the left.
  • 2Instantly see the decoded Header and Payload on the right.
  • 3The tool will automatically validate the token structure.
  • 4Header fields (like 'alg' and 'typ') are highlighted in red.
  • 5Payload data (claims) is highlighted in purple.
  • 6Use the Clear button to reset the tool and start over.
Key Features
  • Client-Side Only: Your secure tokens are decoded right in your browser memory and are never transmitted to any server.
  • Instant Parsing: See the decoded JSON structure immediately as you type or paste.
  • Visual Debugging: distinct color coding helps you understand the three parts of a JWT (Header.Payload.Signature).
  • Error Handling: Get clear feedback if your token is malformed or invalid.

Practical Guidance

When to use this: Use JWT Debugger when you need quick, trustworthy checks for tokens, hashes, credentials, or security-related text without adding extra tooling.

Example workflow:

  1. Open JWT Debugger and paste or upload your source input.
  2. Apply the key option settings for your specific use case.
  3. Review output quality and run a quick sanity check.
  4. Download or copy the final result.

Common mistakes:

  • Pasting malformed input and assuming the output is complete without checking validation errors.
  • Using test data that does not match the real-world format or file type you plan to process.
  • Skipping a final review step before using the output in production or client-facing work.

Privacy note: For most file utilities, processing is performed in-browser and files remain on your device during normal use.

Frequently Asked Questions

Learn More

Need practical guides, walkthroughs, and troubleshooting tips? Explore the Axonix blog for detailed tutorials.

Read Blog Tutorials

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