JWT Decoder

Paste any JSON Web Token into this free decoder and instantly see what is inside it — the header algorithm and key ID, the payload claims with timestamps converted into human-readable dates, and the raw signature bytes. JWTs are everywhere in modern web development, from OAuth flows and single sign-on tokens to API authentication, mobile sessions and microservice traffic, but their compact, base64url-encoded format makes them awkward to inspect by eye. This tool from Chat GPT5 makes that inspection painless: drop a token in the input field, see the decoded JSON with syntax highlighting, and quickly verify what claims are present, whether the token has expired, which audience it was issued for and what algorithm signed it. Everything happens in your browser using only client-side JavaScript, so even tokens that grant sensitive permissions never leave your machine. This is the kind of utility you will reach for during debugging, security reviews, third-party API integrations, and anytime an auth bug pops up at 2am. Bookmark it, share it with your team, and stop pasting production tokens into random websites you found through a search engine.