JWT Decoder – Decode JSON Web Tokens Online
Paste a JWT token to instantly decode and inspect its header, payload, and signature. Everything runs in your browser — your token is never sent to any server.
JWT Decoder
Token Status
Decode a JWT to see its status.
Why Use Tools Oasis JWT Decoder?
Tools Oasis decodes JSON Web Tokens entirely in your browser — your token is never uploaded, logged, or shared. Perfect for debugging authentication flows, inspecting claims, and checking token expiration.
Token exposure risk
Pasting JWTs into server-based tools sends tokens to third-party logging. Tools Oasis decodes entirely client-side.
In-Browser Processing
All logic runs in JavaScript locally — zero server calls, zero latency from network round-trips.
Secure by Default
No logging, no telemetry, no account needed. Your code and data stay yours.
Works Offline
Once the page has loaded, every tool works without an internet connection.
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Try NordPass — Free Password ManagerFrequently Asked Questions
01 What is a JWT (JSON Web Token)?
A JWT is a compact, URL-safe token used for securely transmitting information between parties as a JSON object. It consists of three parts: a header (algorithm and type), a payload (claims/data), and a signature (verification).
02 Is my JWT token sent to any server?
No. Tools Oasis decodes JWT tokens entirely in your browser using JavaScript. Your token is never transmitted, stored, or logged anywhere.
03 Can this tool verify JWT signatures?
This tool decodes and displays the JWT contents but does not verify signatures, as that requires the secret key or public key which should remain private.
04 What do the exp and iat claims mean?
The exp (expiration time) claim specifies when the token expires. The iat (issued at) claim indicates when the token was created. Both are Unix timestamps.
05 Why is my JWT showing as expired?
The exp claim in your token's payload has a timestamp in the past. This means the token is no longer valid and should be refreshed or a new one should be requested from the issuer.
More Questions About JWT Tokens
01 What is a JSON Web Token (JWT)?
A JWT is a compact, self-contained token used for securely transmitting information between parties. It consists of three Base64URL-encoded parts separated by dots: a header (algorithm info), a payload (claims/data), and a signature (for verification).
02 Is it safe to paste my JWT here?
Yes. This tool runs entirely in your browser — your JWT is never sent to any server, stored, or logged. However, you should never share your JWTs publicly, as they may contain sensitive claims and could be replayed if not yet expired.
03 Can this tool verify JWT signatures?
No. This tool decodes and displays JWT contents but does not verify signatures. Signature verification requires the secret key (for HMAC) or the public key (for RSA/ECDSA), which should remain private and server-side.
04 What are common JWT claims like exp, iat, and sub?
exp (expiration time) is when the token expires. iat (issued at) is when the token was created. sub (subject) identifies the principal (usually a user ID). iss (issuer) identifies who created the token. All timestamps are Unix epoch seconds.
05 Where are JWTs commonly used?
JWTs are widely used for API authentication (OAuth 2.0, OpenID Connect), single sign-on (SSO), session management in stateless architectures, and securely passing claims between microservices. They are the standard token format for most modern web applications.