JWT Token Generator & HMAC-SHA256 Builder

Create and verify JSON Web Tokens (JWT) securely in your browser using native Web Crypto HMAC-SHA256 algorithms without external servers.

HMAC Secret Key:
1. Header (Algorithm & Token Type) JSON
2. Payload (Claims & User Data) JSON
3. Generated Signed JWT Token HMAC SHA-256
..
Algorithm: HS256 (HMAC with SHA-256)
Status: 100% Client-Side Web Crypto API

How to Generate JSON Web Tokens (JWT) Online

JSON Web Tokens (RFC 7519) are standard compact URL-safe tokens used for authentication and secure data exchange in modern microservices, APIs, and single-page applications. A valid JWT consists of three dot-separated Base64URL-encoded strings: Header, Payload, and Signature.

Our online JWT generator uses your browser's native Web Crypto API (crypto.subtle.sign) to generate authentic HMAC-SHA256 cryptographic signatures without sending your private secret keys across the internet.

Standard JWT Claims (RFC 7519)

  • sub (Subject): Identifies the principal that is the subject of the JWT (e.g. user ID).
  • name / email: Custom user profile attributes or RBAC role permissions.
  • iat (Issued At): UNIX timestamp indicating when the token was created.
  • exp (Expiration Time): UNIX timestamp after which the JWT must not be accepted by servers.

Frequently Asked Questions (FAQ)

Why should I use a client-side JWT generator instead of online backend servers?
Many online JWT tools transmit your secret keys or user payloads to remote servers for signing. Our tool runs 100% locally in your web browser using HTML5 Web Crypto APIs, guaranteeing zero credential leaks.
What is the difference between Base64 and Base64URL encoding in JWT?
Base64URL encoding replaces standard Base64 characters (+) and (/) with (-) and (_), and removes trailing padding (=) so tokens can be passed safely in HTTP headers and query strings.