JWT Decoder
Decode any JWT token to inspect its header, payload, and signature. View all claims with human-readable timestamps, check expiration status in real-time, and verify token structure. Supports all standard algorithms (HS256, RS256, ES256, etc.). Nothing is sent to any server — your tokens stay in your browser.
Decoded output will appear here
Paste a JWT token on the left to get started
Decode JWT Tokens Instantly — Free & Private
JSON Web Tokens are used everywhere in modern web development — OAuth 2.0, API authentication, SSO, and microservice communication. Debugging authentication issues often starts with inspecting the token.
Our JWT Decoder lets you paste any token and instantly see the header (algorithm, type, key ID), payload (all claims with human-readable timestamps), and signature. Real-time expiration checking tells you exactly whether the token is still valid.
Unlike jwt.io and other online decoders, our tool runs 100% in your browser. Your tokens — which contain user IDs, permissions, and sensitive claims — are never transmitted to any server. For security-conscious teams working with production tokens, this is the only safe approach.
Features
Frequently Asked Questions
What is a JWT token?
A JSON Web Token (JWT) is a compact, URL-safe token format used for authentication and information exchange. It consists of three Base64URL-encoded parts: a header (algorithm and type), a payload (claims/data), and a signature that verifies integrity.
Is it safe to decode JWTs in the browser?
Yes — our decoder runs 100% client-side. Your token never leaves your browser. This is actually safer than using server-based JWT decoders, since JWTs are bearer tokens: anyone with the token can authenticate as that user.
Can this tool verify JWT signatures?
This tool decodes and inspects JWT structure, claims, and expiration. Signature verification requires your secret or public key, which should never be shared with a third-party tool. Verify signatures server-side in your application.
What JWT algorithms are supported?
The decoder works with all JWT algorithms including HS256, HS384, HS512, RS256, RS384, RS512, ES256, ES384, ES512, and PS256. The algorithm is displayed in the decoded header.
How do I check if a JWT is expired?
Paste your token and the decoder automatically checks the 'exp' (expiration) claim against the current time. It shows a clear expired/valid badge and tells you exactly when the token expires or how long ago it expired.
What are JWT claims?
Claims are statements about the user and token metadata stored in the payload. Standard claims include 'iss' (issuer), 'sub' (subject), 'aud' (audience), 'exp' (expiration), 'iat' (issued at), and 'jti' (JWT ID). Custom claims can include roles, permissions, and user data.
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