What is JWT?
A JWT (JSON Web Token) is a compact, signed token format used for authentication and information exchange. It has three base64url-encoded parts separated by dots — header, payload, and signature — and the signature lets a server verify the payload has not been tampered with, without needing a database lookup.
Example
Structure: header.payload.signature, e.g. eyJhbGciOiJIUzI1NiJ9.eyJzdWIiOiIxMjMifQ.abc123.
Related tool
Try it on ToolSphere — runs entirely in your browser, nothing is uploaded to a server.