TOOLS · JWT
Decode a JWT, instantly.
Paste a JSON Web Token to see its header and payload claims, decoded locally in your browser.
What a JWT Actually Is
A JSON Web Token (JWT) is a compact, three-part string used for authentication and authorization: header.payload.signature, each part separately Base64URL-encoded. The header describes the token type and signing algorithm, and the payload carries the actual claims — things like a user ID, role, or expiration time.
This tool decodes the header and payload back into readable JSON. It does not, and cannot, verify the signature — that requires the secret key or public key the token was signed with, which only the issuing server has.
Important Security Note
Never paste a real production authentication token into any online tool, including this one, unless you fully trust how it handles the data. Decoding a JWT reveals its payload in plain text to whoever has the token — that's true by design, since a JWT's claims are only encoded, not encrypted. For debugging, use test tokens whenever possible.
How This Tool Works
Everything happens in your browser using standard Base64URL decoding and JSON.parse — nothing you paste is sent to a server. Common timestamp claims (exp, iat, nbf) are also shown as human-readable dates alongside their raw Unix values.
Related Reading
Frequently Asked Questions
Does this tool verify the JWT's signature?
No. Verifying a signature requires the secret or public key the token was signed with, which this tool never has. It only decodes the header and payload so you can read the claims.
Is it safe to paste a real JWT into this tool?
Decoding happens entirely in your browser, but a JWT's payload is plain, readable data once decoded — never paste a live production token into any online tool unless you're certain about its handling and trust boundary. Prefer test tokens for debugging.
Why do exp, iat, and nbf show two values?
Those are Unix timestamp claims (seconds since 1970), which aren't human-readable on their own, so this tool shows the raw number next to its equivalent calendar date and time.