Online JWT Converter
Online JWT converter to decode a JWT into readable JSON (header, payload), inspect the signature segment, and convert exp/iat/nbf to UTC dates. Also encode an unsigned (alg:none) token locally.
header.payload.signature (JWS). No network requests.alg:none token with an empty signature (ends with a dot). This tool does not sign tokens.How to use
Use it to decode or create simple test tokens.
- Paste a JWT into JWT Input.
- Click Decode JWT to view header/payload JSON and derived time claims.
- Optionally, use Encode (alg:none) to create an unsigned token from header/payload JSON for testing.
FAQ
Does this JWT converter verify the signature?
No. It only decodes and shows the signature segment; use a signing/verifying tool for cryptographic verification.
Is my token sent to a server?
No. The decoder runs locally in your browser and does not make network requests.
Why do I get “JWT must have 3 parts”?
A JWS JWT must be header.payload.signature. If it has fewer/more segments, it won’t decode as a JWT.
Why does decoding fail with “invalid Base64URL length/characters”?
The token contains characters outside Base64URL or has a malformed segment length; re-copy the token without spaces or quotes.
What are exp, iat, and nbf in the output?
They are standard time claims (seconds since Unix epoch). The tool also shows them converted to UTC ISO timestamps.
What does “Encode (alg:none)” mean?
It generates an unsigned token for testing. Many real systems reject alg:none tokens for security.
Can this tool convert a JWT to only the payload JSON?
Yes—decode it and then copy the decoded.payload section from the output.
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