JWT Decoder & Inspector

JWT Token0 chars
Paste a JWT token above to decode and inspect it

What This Tool Does

JWT Decoder & Inspector is built for deterministic developer and agent workflows.

Decode and inspect JSON Web Tokens — header, payload, claims, and expiration.

Use How to Use for execution steps and FAQ for constraints, policies, and edge cases.

Last updated:

This tool is provided as-is for convenience. Output should be verified before use in any production or critical context.

Agent Invocation

Best Path For Builders

Dedicated API endpoint

Deterministic outputs, machine-safe contracts, and production-ready examples.

Dedicated API

https://aidevhub.io/api/jwt-decoder/

OpenAPI: https://aidevhub.io/api/openapi.yaml

GET /api/jwt-decoder/ GET jwt-decoder
POST /api/jwt-decoder/ POST jwt-decoder

Unified Runtime API

https://aidevhub.io/api/tools/run/?toolId=jwt-decoder&a=...

GET and POST are supported at /api/tools/run/ with identical validation and limits.

Limit: req / s, input max 128 KB.

How to Use JWT Decoder & Inspector

  1. 1

    Paste your JWT token

    Copy a JSON Web Token from your auth system (usually from Authorization header or localStorage) and paste it into the decoder.

  2. 2

    View decoded header and payload

    See the token's header (algorithm, type), payload (claims like sub, exp, iat), and signature. All three parts are decoded and displayed separately.

  3. 3

    Check expiry and validate claims

    Look at the `exp` (expiration) claim to see when the token expires. Check `iat` (issued at) and other claims to understand token validity.

  4. 4

    Verify signature with secret

    If you have the secret key, paste it to verify the signature. The decoder shows whether the signature is valid or tampered with.

  5. 5

    Inspect custom claims

    Review all custom claims (roles, permissions, user ID, etc.) in the payload. Use this to debug auth issues and understand token contents.

Frequently Asked Questions

What is JWT Decoder & Inspector?
JWT Decoder & Inspector decodes JSON Web Tokens and displays the header, payload, claims, and expiration details in a readable format. It's a must-have tool for developers working with authentication and authorization.
How do I use JWT Decoder & Inspector?
Paste your JWT string into the input field and the tool instantly decodes it, showing the header algorithm, all payload claims, and expiration status. It highlights whether the token is expired and displays timestamps in human-readable format.
Is JWT Decoder & Inspector free?
Yes. This tool is free to use with immediate access—no account required.
Does JWT Decoder & Inspector store or send my data?
No. All processing happens entirely in your browser. Your JWT never leaves your device — nothing is sent to any server. This makes it safe for inspecting production tokens.
Can it verify JWT signatures?
The tool decodes and displays the header and payload without needing a secret key. Signature verification would require your secret or public key, so the tool focuses on safe, client-side inspection of token structure, claims, and expiration.