JSON Web Token

JWT (JSON Web Token) is a compact, self-contained, and secure method for transmitting information between parties as a JSON object. JWT has become essential for addressing the following needs at scale across enterprise organizations.

• API Authentication - After a user logs in, the server generates a JWT and sends it to the client, which stores it (e.g., in local storage or cookies). The client includes this token in the Authorization header for subsequent requests.
• API Authorization - Servers decode the JWT to verify the user’s identity and permissions before granting access to protected resources.

Enterprise are choosing JWT primairly for internal APIs and microservices, but are also application outside the enterprise for the following reasons.

• Stateless - JWTs are stateless and sessionless, meaning no server-side storage is required. All required user data is embedded in the token itself.
• Portable - JWTs are URL-safe and small in size, making them easy to pass through URLs, HTTP headers, and query strings.
• Scalable - Since JWTs do not require session storage, they are highly scalable for distributed systems and microservices.
• Flexible - JWTs allow you to include custom claims, such as user roles and permissions, enabling fine-grained access control.
• Cross-Domain Authentication - JWTs work well in Single Sign-On (SSO) scenarios, enabling seamless authentication across different domains and services.

JWT is a secure, scalable, and stateless way to handle authentication, authorization, and secure data transmission. It is widely used in HTTP APIs, microservices, as well as Single Sign-On (SSO) systems, providing flexibility and security for modern applications and integrations.