JWT Decoder

When this tool is a good fit

JWT Decoder helps when you need decoded JSON header and payload plus claim timing details from a JWT string with header, payload, and signature segments. It is most useful for inspecting JWT headers and payload claims during authentication, API debugging, and expiration checks. The notes below focus on the settings that matter, the checks worth doing before you export, and the limits that tend to cause mistakes.

• Takes a JWT string with header, payload, and signature segments.
• Lets you adjust which token to inspect and whether timestamps should be compared with local or UTC time.
• Calls out what to review: exp, iat, nbf, iss, aud, scope, alg, and whether the token is expired.
• Produces decoded JSON header and payload plus claim timing details.
• Fits common jobs such as inspecting JWT headers and payload claims during authentication, API debugging, and expiration checks.

Example jobs

• Decode an access token payload during local API debugging.
• Check whether exp has already passed.
• Inspect alg and typ fields in a token header.

How to use JWT Decoder

1. Prepare a JWT string with header, payload, and signature segments.
2. Set which token to inspect and whether timestamps should be compared with local or UTC time before running the tool.
3. Generate or process the result, 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. Run a second pass if the destination system, document, or workflow has stricter requirements.

What to know before you use it

• 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.
• 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.

Checks and edge cases

• 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