- What is JWT Decoder best for?
- Decode and inspect JWT (JSON Web Token) header and payload. Note: signature is not verified.
- Does JWT Decoder upload or store my data?
- This text tool is local-first in the browser and does not store your input for normal conversion workflows.
- Does JWT Decoder verify token signatures?
- No. This tool decodes header and payload only for inspection. Signature verification requires the secret key and proper cryptographic libraries. Never trust a JWT's claims without verified signature.
- What does 'invalid token' mean?
- A JWT must have three parts separated by dots (header.payload.signature). If you see this error, check for: missing or extra dots, invalid Base64URL encoding, or pasting the full token including 'Bearer ' prefix.
- How do I check if a token has expired?
- After decoding, look for the 'exp' (expiration) claim in the payload. The value is a Unix timestamp in seconds. Compare it to the current time. If exp < now, the token is expired.
- Can I decode JWTs from any algorithm (HS256, RS256, ES256)?
- Yes. The decode tool works with any algorithm because it only reads the Base64URL-encoded header and payload. Signature verification is separate and not implemented here.
- Which tools pair well with JWT Decoder?
- Common next steps include Hash Generator, Base64 Encode/Decode. These related tools help continue the same workflow through generation, validation, formatting, or debugging.