What is JWT Decoder?
A JSON Web Token (JWT) is made of three dot-separated, Base64URL-encoded parts: header, payload and signature. This decoder splits the token and shows you the readable content of the header and payload, so you can verify claims like the subject (sub), role, issuer or expiry (exp) without needing the secret key.
It's essential when debugging authentication: checking why a token is rejected, seeing whether it has already expired, or reviewing what information it carries. Remember that decoding is not the same as verifying the signature; still, being able to read the content instantly saves a lot of time. The token is processed in your browser and never sent to any server.
Frequently asked questions
Is it free?
Yes, all NewKit tools are completely free.
Is my data sent to a server?
No. Processing happens 100% in your browser, so it is safe even for sensitive data.