Spring Boot REST API Timeout Issue – Causes and Solutions
REST API timeout issues are one of the most common production problems in Spring Boot applications. A request works fine locally but fails in production with: 504 Gateway Timeout 408 Request Timeout Connection timed out SocketTimeoutException Read timed out In this article, we’ll explain: Why timeouts happen Where they occur (client, server, proxy) How to configure proper timeouts Best practices to prevent them 1️⃣ Where Does Timeout Actually Happen? Timeout does not always mean your code is slow. It can happen at: 1️⃣ Client (RestTemplate / WebClient) 2️⃣ Server (Tomcat) 3️⃣ Load Balancer (Nginx / Apache) 4️⃣ API Gateway 5️⃣ Database 6️⃣ External API call You must first identify where the timeout originates. 2️⃣ Common Causes of Timeout 🔹 Slow Database Queries Missing indexes Large result sets Table locks 🔹 Blocking External API Calls Third-party API slow Network latency 🔹 Thread Pool Exhaustion Too many concur...