Does this verify the signature?

No. This tool decodes JWTs locally. It does not verify signatures. Never treat a decoded token as trusted.

Is the token uploaded?

No. Decoding happens in your browser. Avoid pasting production secrets into any shared device.

Developer Tools

Decode a JSON Web Token header and payload locally. This tool does not verify signatures.

This tool decodes JWTs locally. It does not verify signatures.

Token

Paste a JWT. The tool splits the three Base64URL parts, decodes the header and payload as JSON, and leaves the signature untouched.

A token starting with eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJzdWIiOiIxMjM0In0 decodes to an HS256 header and a payload with a sub claim.

Percent of, change, and difference.

Exact age, totals, and next birthday.

Estimate investment growth over time.

Monthly payment and amortization summary.