JWT Decoder
Decode JWT headers and payloads locally and inspect time-based claims such as expiration
What this tool does
Split a JWT into its Header, Payload, and Signature sections and display its JSON claims and time values in a readable form. This helps when debugging OAuth, OpenID Connect, and API authentication flows.
Common use cases
- Inspect a development token returned by OAuth or OpenID Connect.
- Check issuer, audience, subject, and custom claims during API debugging.
- Convert exp, nbf, and iat values to dates and check their current status.
How to use it
- Paste a JWT containing three dot-separated segments.
- Review the decoded Header and Payload JSON.
- If exp, nbf, or iat is present, check the displayed date and status.
Input and output example
Input: A JWT whose payload contains { "sub": "user-123", "exp": 1893456000 }
Output: The formatted subject claim and an expiration time of 2030-01-01 00:00:00 UTC
Important notes
- This tool does not verify the signature. Decoded claims must not be treated as authentic or untampered.
- Production JWTs can contain sensitive data. Take care on shared devices and during screen sharing.
- Expiration status is calculated using your device clock.
Frequently asked questions
- Can this tool detect a modified JWT?
- No. It only decodes the token and does not verify its signature with a public key or secret.
- Is my JWT sent to a server?
- No. Decoding happens entirely inside your browser.