Introduction Duplicate requests are one of the most damaging bugs in production REST APIs — a user double-clicks “Pay Now,” a mobile client retries after a network blip, or a load balancer resends a request that never got acknowledged. Without protection, this can mean double-charged customers, duplicate orders, or duplicate emails sent. What makes this […]

A response timeout happens when a client (browser, mobile app, another microservice, or a load balancer) gives up waiting for your Spring Boot API to finish responding. Unlike a request timeout (client failing to send data in time), a response timeout means the server accepted the request but couldn’t finish processing and writing the response

Introduction One of the most common errors developers encounter while building REST APIs is the HTTP 404 Endpoint Not Found response. Unlike an HTTP 500 Internal Server Error, which indicates a server-side failure, a 404 means the requested resource or endpoint could not be located. Although a 404 appears straightforward, identifying the root cause can

Introduction A request timeout is one of the most frustrating production issues in Spring Boot applications. Users click a button, wait for several seconds, and eventually receive an error instead of the expected response. Unlike an HTTP 500 Internal Server Error, where the application fails immediately, a timeout indicates that the server did not complete

Global exception handling is one of the most important features in any Spring Boot REST API. Instead of returning stack traces or inconsistent error responses, it allows you to handle exceptions in one central location using @ControllerAdvice and @ExceptionHandler. However, many developers encounter situations where global exception handling simply doesn’t work. Common symptoms include: This