JWT Decoder
Read inside a JWT.
Paste a JSON Web Token to decode and pretty-print its header and payload — entirely in your browser.
What is the JWT Decoder?
BYAFT's JWT Decoder reads the header and payload of a JSON Web Token, right in your browser. It base64url-decodes each section and pretty-prints the JSON so you can inspect the claims — no sign-up, and nothing uploaded.
It decodes only and does not verify the signature, so treat it as a read-only inspector and avoid pasting tokens that contain secrets.
How to use the JWT Decoder
- 1Paste your tokenDrop the JWT (header.payload.signature) into the input.
- 2Read the sectionsThe decoded header and payload appear side by side.
- 3Copy what you needCopy the header or payload JSON.
What you can use it for
- Inspecting the claims in a token while debugging
- Checking a token’s expiry or issuer
- Confirming which algorithm a token uses
- Reading a payload without a backend
Frequently asked questions
Does it verify the signature?
No. It decodes and displays the header and payload only — it does not verify the signature. Do not paste tokens containing secrets.
Is the token uploaded?
No. Decoding happens entirely in your browser; the token never leaves your device.
Is it free?
Yes — decoding JWTs is free with no sign-up.