This online JWT decoder and verifier decodes JSON Web Tokens and inspects header, payload and signature data instantly.
Quickly decode JWT tokens and verify JWT signatures in your browser with no server upload.
A JSON Web Token (JWT) is a compact, URL-safe open standard (RFC 7519) for securely transmitting claims between two parties as a JSON object. JWTs are self-contained, digitally signed, and are the de-facto token format for modern authentication, authorization, single sign-on and stateless APIs.
A JWT is made of three Base64URL-encoded parts separated by dots: header.payload.signature. Decoding a JWT reveals the algorithm, token type, user identity, expiration and any custom claims packed into the token.
Decoding JWTs online is essential while debugging authentication flows, inspecting API requests, validating third-party identity tokens, or understanding claims returned by OAuth 2.0 and OpenID Connect providers. A quick online JWT decoder lets you see exactly what a token contains without writing extra code.
This is especially useful for frontend developers, backend engineers and QA engineers who frequently work with bearer tokens, access tokens and ID tokens across multiple environments.
Using our JWT decoder is simple and runs entirely in your browser:
Our JWT decoder prioritises privacy, speed and accuracy. All parsing and signature verification happen on the client side, so tokens never leave your browser. It supports HMAC verification (HS256, HS384, HS512), Base64-encoded secrets and automatic algorithm detection from the token header.
With real-time decoding, syntax-highlighted JSON output and zero tracking, it is designed as a professional tool for developers, security engineers and DevOps teams working with authentication every day.
A JWT consists of three Base64URL-encoded segments joined with dots. The header describes the token type and signing algorithm (for example { "alg": "HS256", "typ": "JWT" }). The payload contains the claims such as sub, iat, exp, iss and any custom data about the user or session.
The signature is computed by signing base64url(header) + "." + base64url(payload) with a secret or private key using the algorithm declared in the header. Base64URL encoding is a URL-safe variant of Base64 that replaces +, / and padding characters so the token can travel safely in URLs, headers and cookies.
This JWT decoder and verifier is packed with features designed for real-world authentication debugging:
kid) and token type.exp) and issued-at (iat) awareness in the decoded payload.JWTs power a huge range of authentication and authorization scenarios: login sessions for single-page applications, bearer-token authentication for REST and GraphQL APIs, OAuth 2.0 access and refresh tokens, OpenID Connect ID tokens, machine-to-machine service credentials and stateless microservices communication.
Developers use an online JWT decoder to debug failing logins, inspect third-party identity tokens (Auth0, Okta, Keycloak, Firebase, AWS Cognito), verify claims propagated between microservices, or confirm that tokens issued by their own backend contain the expected data and expiration.
Yes — this tool is built with privacy as a top priority. All JWT parsing and signature verification runs entirely in your browser using client-side JavaScript. Tokens and secret keys are never uploaded, logged or stored on any server.
Even so, treat production JWTs as credentials. Never paste production secret keys or long-lived access tokens into any third-party tool, including this one. For sensitive debugging, use short-lived test tokens or locally issued tokens, and rotate any secret that you may have exposed accidentally.
Among the many JWT tools available online, DevTools stands out for its focus on speed, privacy and developer ergonomics. It is 100% free, free of ads and trackers, and designed by developers for developers who need a reliable daily utility.
Whether you decode JWTs occasionally or dozens of times per day, this tool delivers a clean, consistent experience. It is part of a comprehensive suite of developer utilities that covers encoding, formatting, conversion and inspection workflows.
Once a JWT is decoded, you can copy the header or payload JSON to your clipboard with a single click. This makes it easy to share the decoded structure with teammates, paste it into a bug report, or feed it into another tool for further processing.
For deeper inspection you can combine this decoder with other DevTools utilities such as the Base64 encoder and decoder, the URL encoder and decoder, and the JSON formatter to pretty-print the decoded payload, inspect URL-encoded bearer tokens or explore custom Base64-encoded claims.
If your JWT uses asymmetric signatures (RS256, ES256, PS256) and ships with an x5c or x5t#S256 header, or if the surrounding OAuth / OpenID Connect stack relies on X.509 certificates, open the ASN.1 Viewer & X.509 / PKCS Decoder to inspect the raw certificate chain, the subject and issuer DN, the public key algorithm and the extensions used to bind the signing key to an identity.
Yes, it's completely free with no registration, ads, or usage limits.
No, all decoding and signature verification is performed locally in your browser. Your tokens and secret keys never touch our servers.
HMAC algorithms HS256, HS384 and HS512 are supported for signature verification directly in the browser. Asymmetric algorithms such as RS256 or ES256 can still be decoded, but their signatures must be verified on a server that has access to the public key.
Paste the JWT into the input field, then enter the matching secret key in the verification panel. The algorithm is auto-detected from the token header, and a green "Signature Verified" badge confirms the token has not been tampered with.
These are standard registered JWT claims defined in RFC 7519: iss (issuer), sub (subject / user ID), aud (audience), exp (expiration time as a Unix timestamp) and iat (issued-at time). Tokens may also include custom claims specific to your application.
Yes. Decoding a JWT only reads its header and payload, so expired tokens are fully decodable. Signature verification is independent of the exp claim — your application is responsible for rejecting expired tokens at authentication time.
All processing in this tool happens client-side, so tokens are not uploaded. Still, treat JWTs as credentials — avoid pasting production tokens or production secret keys into any third-party tool, and rotate any key that may have been exposed.
A signed JWT (JWS, RFC 7515) is integrity-protected but its payload is only Base64URL-encoded, not encrypted — anyone can read it. An encrypted JWT (JWE, RFC 7516) keeps the payload confidential. This tool works with signed JWTs, which are the most common format used in authentication.
To deepen your understanding of JSON Web Tokens and related security best practices, here are authoritative external resources: