Tools Encoding & Data

JWT Decoder

Decode JWT headers and payloads to inspect claims during development, with optional HMAC signature checks.

JWT Decode & Validate


          
        

      

    


    
    
    		


					

				
JWT Decoder splits a compact token into header, payload, and signature views so you can read claims like sub, roles, and exp while debugging login flows.
Paste the JWT, optionally pick an HMAC algorithm and secret, then validate the signature if you are testing HS256. Copy each section independently when filing a bug.
Treat production secrets as sensitive: prefer disposable test keys when validating signatures in a browser tool.
What JWT Decoder does
Inspect JWT structure and optionally verify HMAC signatures.
  • JWT token textarea
  • Algorithm select defaulting to HS256
  • Optional secret key field for HMAC validation
  • Validate Signature action
  • Separate header, payload, and signature outputs with copy buttons
  • Expiry status badge on the payload panel
Who JWT Decoder is for
  • Auth developers tracing claim mismatches
  • Mobile engineers comparing tokens across environments
  • Security reviewers checking claim contents in staging
  • Support engineers confirming expiry on a reported session
How to use JWT Decoder
1. Open JWT Decoder on beeforge.dev.
2. Paste the token into JWT Token.
3. Review Header and Payload panels as they populate.
4. Optionally enter a secret, confirm Algorithm, and click Validate Signature.
5. Copy header, payload, or signature sections as needed.
Features
  • Three-part token breakdown
  • Optional signature validation for HMAC algorithms
  • Visual expiry cue on the payload
  • Per-section copy controls
  • Development-oriented layout without an auth dashboard
Examples
  • Confirm an access token includes the expected audience claim before calling an API.
  • Check whether exp is already in the past when a client reports random logouts.
  • Validate an HS256 test token against a local secret during tutorial work.
Tips and limits
  • Never paste production signing secrets into any online tool if your policy forbids it.
  • Decoding does not prove integrity unless signature validation succeeds with the correct key.
  • RS256 and other asymmetric schemes need different verification than a shared HMAC secret.
  • Base64url padding differences can break naive decoders; use this UI rather than hand edits.
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FAQ
Does decode equal verify?
No. Anyone can decode claims. Trust requires signature verification with the correct key material.
Where is my token processed?
Parsing runs in the browser. Still avoid pasting production tokens that contain sensitive personal data.
Why is signature invalid?
Wrong secret, wrong algorithm, or a token truncated in transit. Confirm all three parts are present.
Can it create tokens?
This module focuses on inspection and optional HMAC validation, not minting production JWTs.
What does the expiry badge mean?
It reflects the exp claim relative to your local clock when the claim is present.
			

		
					

				

	
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