The JSON.rs JWT tool turns opaque tokens into readable authentication data. Decode headers, inspect claims, edit payloads, sign test tokens, and validate signatures locally while debugging APIs, identity providers, staging environments, and authorization flows.
A JWT is easy to copy but hard to reason about in its compact form. Paste a token to reveal the header, payload, signature state, timestamps, issuer, subject, audience, scopes, and custom claims in a structure that is easy to inspect.
alg, typ, and key identifiers.iss, sub, aud, exp, iat, and custom fields.Signature validation helps separate bad data from bad configuration. Add an HMAC secret or RSA public key to confirm whether a token was signed with the expected key, then use history and autosave to move between recent debugging cases.
Authentication failures often hide in small details: expired tokens, wrong audiences, missing scopes, unexpected algorithms, copied whitespace, or mismatched signing keys. A readable decoder helps confirm what your API actually receives.
The JWT page is built for browser-side inspection. Decoding, editing, signing, validation, autosave, and history stay local, which is especially useful for test credentials, staging tokens, internal services, and private API payloads.
A JSON Web Token contains three Base64URL sections. This tool separates those sections, renders the JSON clearly, and shows whether the signature can be verified with the key material you provide.
After decoding a JWT, use the JSON formatter to clean up copied claims or Text Diff to compare two token payloads, permission sets, or environment-specific authentication responses.