JWT Decoder

Where it fits

Use JWT Decoder for inspecting JWT headers and payload claims during authentication, API debugging, and expiration checks. It works well when you want decoded JSON header and payload plus claim timing details and do not need a bigger workflow around it.

• Best fit: inspecting JWT headers and payload claims during authentication, API debugging, and expiration checks.
• You start with a JWT string with header, payload, and signature segments.
• The useful choices are which token to inspect and whether timestamps should be compared with local or UTC time.
• Check exp, iat, nbf, iss, aud, scope, alg, and whether the token is expired.
• You end up with decoded JSON header and payload plus claim timing details.

What the output does and does not prove

• The first two JWT segments are Base64URL decoded and parsed as JSON.
• The signature is detected but not verified.
• Time claims are shown as Unix values and readable local times.

A clean way to use JWT Decoder

1. Start with a JWT string with header, payload, and signature segments.
2. Choose which token to inspect and whether timestamps should be compared with local or UTC time.
3. Run the tool once, then review exp, iat, nbf, iss, aud, scope, alg, and whether the token is expired.
4. Copy, export, or download decoded JSON header and payload plus claim timing details.
5. Treat the output as one checkpoint, then verify the next step in the real workflow.

What to watch for

• Decoding a JWT does not verify its signature or prove the token is trustworthy.
• Claims are Base64URL-encoded JSON and can be read by anyone who has the token.
• Never paste live production bearer tokens into shared screenshots or tickets.
• Use server-side verification for authorization decisions; this tool is for inspection only.

How your data is handled

The token is decoded locally and is not uploaded. Avoid pasting sensitive production tokens unless you understand the risk.

FAQ