Developer security
JWT Decoder
Header / Payload / Signature with expiry check
🔒 See this tool’s privacy notes for local processing and external service details. Site analytics are described in our privacy policy.
Header
—
Payload
—
Signature
—
Decodes only — does not verify signature.
Quick guide
What can JWT Decoder help you do?
Free JWT decoder. Shows header, payload, signature, and expiry status. Browser-only — your token stays private.
Best for
Inspect a JWT Header, Payload, and Signature during API or OAuth debugging, and convert iat and exp to dates. Decoding cannot prove validity.
How to use it
Paste a JWT with three dot-separated parts. Header and Payload show JSON; Signature stays encoded, while iat and exp show timing details.
How to read the result
Valid only means exp has not passed and parsing worked; Signature was not verified. Device time affects displayed dates.
Privacy and limits
Decoding stays in your browser. Never paste a production access token, session cookie, or unredacted personal claims.
Signature, alg, iss, aud, and revocation are not verified. Enforce algorithms and keys server-side.
Frequently Asked Questions
What is a JWT?
JSON Web Token — three Base64-encoded parts used for API auth and sessions.
Does this verify signatures?
No — verification requires the secret key from your server.