JWT Generator & Bearer Token Creator - Secret Key Generator Online

What is a JWT (JSON Web Token)?

JWT (JSON Web Token) is an open standard (RFC 7519) that defines a compact and self-contained way for securely transmitting information between parties as a JSON object. JWTs are digitally signed using a secret (with HMAC algorithms) or a public/private key pair (RSA or ECDSA). Because of their compact size, JWTs can be sent through a URL, POST parameter, or inside an HTTP header. They are self-contained, containing all necessary information about the user, and are secure, as the digital signature verifies authenticity and prevents tampering. They are also stateless, eliminating the need to store session information on the server.

How to Use the JWT Generator and Decoder

Step 1: Select Operation Mode - Choose 'JWT Decoder' to analyze an existing token or 'JWT Encoder' to create a new one.
Step 2: Decoder Mode - Paste a JWT token, and the tool will automatically parse and display the header and payload. Enter a secret to verify the signature.
Step 3: Encoder Mode - Edit the header (select algorithm) and payload (add claims), then enter a secret to automatically generate the JWT.
Step 4: Use the Result - Copy the generated token for use in your application, or review the decoded information for debugging and validation.

Frequently Asked Questions about JWT

What are the common use cases for JWT?

JWTs are widely used for: User Authentication (maintaining session state without server-side storage), API Authorization (protecting REST APIs and microservices), Single Sign-On (SSO), Information Exchange, Mobile App Authentication, and Microservice Communication.

Which JWT algorithms do you support?

Our tool supports the most common HMAC-based JWT signing algorithms: HS256 (HMAC SHA-256), HS384 (HMAC SHA-384), and HS512 (HMAC SHA-512).

What are some JWT security best practices?

Use strong, randomly generated secrets. Always set an appropriate expiration time (exp claim). Never store sensitive information like passwords in the payload. Implement a token refresh mechanism for long-lived sessions. Always validate the JWT signature on the server-side. Use HTTPS to prevent token interception.

What are the standard JWT claims?

Pre-defined claim names for interoperability include: iss (Issuer), sub (Subject), aud (Audience), exp (Expiration Time), nbf (Not Before), iat (Issued At), and jti (JWT ID).

What are common JWT issues and their solutions?

Invalid JSON format in payload: Ensure your payload is valid JSON. Token has expired: Check the 'exp' claim value. Signature verification failed: Verify you are using the correct secret and algorithm. Malformed JWT: A JWT must have three parts separated by dots (header.payload.signature).

JWT Generator