About JWT Decoder
Decode JWTs online to inspect the header and payload without pasting tokens into a third-party server. This JWT decoder helps you read alg/typ, claims, and expiry while debugging auth. Signature verification is a separate step and is not assumed from decoding alone. Because tokens often carry session data, DevTooKit keeps decoding fully local.
What stays local: Access tokens, ID tokens, and session JWTs.
What you can do with JWT Decoder
- Decode header and payload (claims)
- Inspect algorithm and token type
- Review expiry and standard claims
- Local-only — tokens never uploaded
How to use JWT Decoder
- Paste the JWT. Paste a compact JWT (header.payload.signature) into the decoder.
- Inspect header. Review alg, typ, and other header fields.
- Inspect payload. Read claims such as sub, exp, iat, and custom fields.
- Debug carefully. Use decoded claims for debugging only — do not share production tokens.
Examples
Typical structure
Input
header.payload.signature
Output
JSON header + JSON payload (signature not verified by decode alone)
Privacy
What stays local: Access tokens, ID tokens, and session JWTs. DevTooKit is local-first — no signup wall, no server-side processing for this tool, and no watermark on results.
Related tools
FAQ — JWT Decoder
Privacy, offline use, and how this free online tool works.
Does this JWT decoder verify the signature?
It decodes and inspects header and payload. Signature verification needs your secret or public key and is not assumed from decoding alone.
Are my tokens uploaded?
No. JWTs are decoded in your browser and never sent to DevTooKit for processing.
Is the JWT decoder free?
Yes — free, no account, no watermark.
Can I use it offline?
Yes after installing the DevTooKit PWA.