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JWT Token Decoder & Inspector

Decode and inspect JSON Web Tokens (JWT) instantly in your browser. Verify token structures, algorithms, payload claims, and expiration timers in real-time.

Last Updated: May 2026

Awaiting Encoded JWT

Input your JSON Web Token string above to instantly inspect its inner claims, cryptographic algorithm, and validation lifespan.

How to Decode JSON Web Tokens Online

  1. 1

    Paste Your Encoded Token

    Copy the raw JWT string (including dots) from your authorization header or API client and paste it into the token input field.

  2. 2

    Inspect Decoded Claims

    The token header and payload segments will be decoded instantly. Inspect metadata like the encryption algorithm, user credentials, and active claims.

  3. 3

    Check Expiration and Signatures

    View the localized expiration datetime and copy specific JSON sections directly to your clipboard for local debugging.

Why Use Our JWT Decoder Tool?

Debugging authentication issues in modern web applications can be difficult when tokens are encoded. Our JWT Decoder lets you inspect the structure of your JSON Web Tokens instantly without needing command-line tools. If a user is denied access, you can paste their token to see if their roles/permissions are correct or if their token has already expired. With clean syntax highlighting and absolute privacy guarantees (all computations run completely in-browser), our tool is a premium utility for security engineers, system architects, and web developers.

Common JWT Claims Explained

  • sub (Subject): The unique identifier of the user or principal whom the token represents.
  • iss (Issuer): The authority or server that generated and issued the token.
  • iat (Issued At): The exact Unix timestamp indicating when the token was created.
  • exp (Expiration Time): The Unix timestamp after which the token must no longer be accepted for authentication.
  • aud (Audience): Identifies the specific recipients or services the JWT is intended for.

Frequently Asked Questions

What is a JWT (JSON Web Token)?

A JSON Web Token (JWT) is a compact, URL-safe standard (RFC 7519) used to securely transmit structured information between parties as a JSON object. This information is digitally signed using a secret key (with HMAC algorithm) or a public/private key pair (using RSA or ECDSA), enabling verification of claims.

Is it safe to paste my JWT token here?

Yes, 100% safe. SnapTool performs all Base64URL decoding and parsing locally within your web browser. Your token, credentials, and payload data are never transmitted over the network or saved on any database server. It is completely safe to inspect sensitive tokens here.

What are the three parts of a JWT token?

A JWT is composed of three segments separated by dots (header.payload.signature): (1) Header: Specifies the token type and cryptographic signing algorithm (e.g. HS256, RS256). (2) Payload: Contains the statements or claims (e.g., user ID, permissions, expiration timestamp). (3) Signature: Created by taking the encoded header, encoded payload, and signing them with a secret key.

How do I check if my JWT is expired?

The token payload typically contains a standard 'exp' (expiration) claim which stores a Unix timestamp (seconds since Epoch). Our JWT Decoder automatically reads this timestamp, translates it into your local date and time, and displays a prominent warning card if the current time exceeds the expiration date.

What is the difference between encryption and signing in a JWT?

Standard JWTs are signed, not encrypted. Signing only ensures *integrity and authenticity* — meaning anyone can decode and read the base64 payload contents, but they cannot modify it without breaking the signature. For sensitive private data transmission, JWE (JSON Web Encryption) should be used instead.

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