Decode, verify claims, inspect headers, and check token expiry.
Execution runs 100% locally inside the browser sandbox using HTML5 Canvas, Web Cryptography Subtle API, and Web Workers. Zero egress.
Zero network latency. Operates completely offline with zero dependencies on third-party backend servers or cloud services.
Built according to official RFC specifications, cryptographic test vectors, and enterprise-grade data transformation standards.
Paste your JWT string (header.payload.signature) into the input box.
View the decoded algorithm, issued-at timestamp, and custom payload claims.
Check if the token is currently active or expired with local system clock validation.
Yes. Unlike other websites, Utilifi decodes tokens 100% in your local browser memory using JavaScript. No tokens or secrets are ever sent to any remote server.
Yes, it inspects the algorithm type and signature segment format client-side.
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