Spring CORS Guide: What It Is and How to Enable It

Cross-Origin Resource Sharing (CORS) is a security feature implemented in modern browsers to prevent unauthorized cross-domain requests, which could otherwise be exploited in attacks such as Cross-Site Request Forgery (CSRF). Initially proposed in the early 2000s, CORS requires that a server explicitly permit requests from a different origin, defined by the combination of protocol, domain, and port. This mechanism allows legitimate cross-domain interactions, such as accessing APIs from a different subdomain or third-party services, while preventing malicious activities. In the Spring Framework, CORS can be configured at the method, class, or global level with specific annotations to allow requests from certain origins, while Spring Security requires additional configuration to bypass its default blocking of preflight requests. By strategically enabling CORS, developers can create more responsive applications without compromising security. This article was authored by Alexander Fridman, a seasoned software industry professional with over 11 years of experience, specializing in backend development.