JWT Decoder
Inspect a JSON Web Token's header and payload.
Input
Output
About JWT Decoder
A JSON Web Token (JWT) is the standard way modern APIs prove who you are: a header, a payload of claims, and a signature, each Base64-encoded and joined with dots. This decoder splits a token and shows the header and payload as readable JSON — useful when debugging auth flows, checking expiry times, or inspecting what claims a token actually carries.
How to use JWT Decoder
1
Paste the token
Paste the full JWT — the three dot-separated parts starting with eyJ. Click Sample to see one.
2
Read header and payload
Both are decoded and pretty-printed. Look for claims like exp (expiry), sub (subject) and iat (issued at).
3
Check the timestamps
exp and iat are Unix timestamps (seconds). An expired exp is the most common reason a token is rejected.