Free JWT Decoder Online

The JWT Decoder is a free online tool that decodes JSON Web Tokens to display the header, payload, and signature information in a readable format.

Yes, it is completely free with no registration required. All decoding happens client-side in your browser, so your tokens are never sent to any server.

The JWT Decoder displays the algorithm, token type, expiration time, issuer, subject, and all custom claims stored in the JWT payload.

Absolutely. The JWT Decoder processes everything client-side in your browser. No data is uploaded to or stored on any server. Your content remains private on your device at all times.

Yes, the JWT Decoder is fully responsive and works on smartphones and tablets. You can use it on any device with a modern web browser -- no app download required.

No account or registration is needed. Simply open the JWT Decoder in your browser and start using it immediately. There are no sign-up walls or usage restrictions.

Simply enter your input in the provided field, adjust any settings to your preference, and the tool will process it instantly. You can then copy the result to your clipboard or download it.

The JWT Decoder works in all modern browsers including Chrome, Firefox, Safari, Edge, and Opera. For the best experience, use the latest version of your preferred browser.

Reading a JWT is safe because the header and payload are only Base64URL-encoded, not encrypted — anyone holding the token can decode them, so inspecting the claims reveals nothing that was meant to stay secret. The real risk is where the token travels: a live access token is an active credential, so pasting one into a service that transmits it to a server could expose your session. This tool avoids that entirely by decoding everything locally in your browser; the token is never uploaded, logged, or stored remotely. As a precaution, only decode tokens you are authorized to inspect, treat any active token as a password you would not paste publicly, and avoid sharing the URL or a screenshot of the decoded payload. Paste your token above to see its claims decoded instantly, entirely client-side with nothing leaving your device.

Decoding and verifying are two separate operations. Decoding simply Base64URL-decodes the header and payload so you can read the claims — it requires no key and proves nothing about authenticity. Verifying means recomputing the signature with the issuer's secret or public key and confirming it matches, which is the only way to know the token was not tampered with or forged. This decoder reads the token and displays the raw signature segment for reference, but it does not cryptographically check it, so treat a decoded payload as informational rather than proof. To actually verify, you need the signing key, which should stay on your backend. The Snippets tab provides ready-made verify-and-sign code for Node.js, Python, Go, Java, PHP, and Ruby so you can validate the token correctly in your own service.

Expiry lives in the exp claim, a Unix timestamp (seconds since 1970) marking the moment the token stops being valid. Two related claims set the window: iat is when the token was issued and nbf is the earliest time it may be used. Raw numbers are hard to read, so this decoder converts exp, iat, and nbf into human-readable dates and shows a live status indicating whether the token is currently valid, expired, or not yet active. That makes "why am I getting a 401?" bugs obvious in seconds — an expired exp is one of the most common causes. Keep in mind these timestamps are world-readable and unverified until you check the signature, and that they are recorded in UTC, so factor in your own time zone when reading them. Paste your token to see its issued-at, not-before, and expiry times decoded into clear dates at a glance.

A JWT has three dot-separated parts: header.payload.signature. The header describes how the token is signed — mainly the alg (signing algorithm, such as HS256 or RS256) and typ (token type). The payload carries the claims: statements about the user or session like iss (issuer), sub (subject), aud (audience), exp (expiry), and any custom or OIDC fields your system adds. The signature, computed from the header and payload using a key, is what lets a server verify the other two parts were not altered. This decoder splits the token automatically, labels the algorithm as symmetric or asymmetric, and explains each registered claim in plain English. Because both header and payload are merely encoded, never store passwords or secrets in them. Paste a token above to see its header and claims separated and described.

Yes — the Builder tab lets you compose a JWT structure for testing. Pick a signing algorithm, set an expiry in minutes, and add your own claims, and it assembles the matching header and payload for you. Crucially, the output is intentionally unsigned: it includes a placeholder where the real signature belongs, which you generate on your backend. This is deliberate, because signing in the browser would expose your secret — a symmetric HS256 key, for example, must stay server-side, or anyone viewing the page source could forge valid tokens. So the Builder is ideal for mocking up token shapes, prototyping claim sets, or producing sample payloads for documentation, not for issuing production credentials. Switch to the Builder tab to draft a token structure, then sign it securely in your own service.