JWT Decoder
Decode a JWT header and payload locally. Decoding is not verification.
Decoding a JWT does not verify its signature. This tool only reads the header and payload.
Input
Output
About this tool
A JWT is three Base64URL parts: header, payload, signature. This tool only Base64-decodes the first two and parses JSON. It does not check the signature.
How it works
Paste a token. Header and payload appear as JSON. Treat the contents as untrusted until you verify the signature with the correct key.
JSON.parse(base64url(part))
Examples
Three parts
header.payload.signature — only the first two parts are decoded here.
FAQ
Does this verify the signature?
No. Decoding is not verification. Anyone can mint a token with a fake payload.
Is the token uploaded?
No. Decoding happens in your browser.