JWT Decoder
Decode JWT header, payload, and signature parts instantly.
Open JWT Decoder
JWT Encoder
Encode JWT header and payload JSON into a token.
HMAC: paste the shared secret. RSA/EC: paste PKCS#8 private PEM or a private JWK JSON object.
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Frequently asked questions
Common questions about this tool.
It Base64URL-encodes your header and payload JSON and combines them with the signature text into the standard three-part JWT format.
No. It only encodes parts. Real JWT signing must be done with a server-side library and the correct secret or private key.
If signature is empty, the token is still rendered as three parts with an empty third segment, so you will see a trailing dot.
A typical header includes typ and alg fields, such as {"typ":"JWT","alg":"HS256"}, but exact values depend on your auth system.
Standard claims include iss, sub, aud, exp, nbf, and iat, plus app-specific claims like roles or tenant IDs.
Yes, open the JWT decoder tool to inspect the encoded output, but signature verification still requires trusted backend key material.