Client-to-Client Communication with OpenFeign in Spring Boot

In a microservices architecture, services often need to communicate with each other to fulfill a request. While RestTemplate or WebClient are commonly used, OpenFeign offers a declarative and cleaner alternative for inter-service communication.

OpenFeign is a Spring Cloud project that enables declarative REST clients to call other microservices directly as if calling local methods.

In this post, we’ll explore how to set up client-to-client communication with OpenFeign in a Spring Boot microservice environment using Eureka for service discovery.

Client-to-Client Communication with OpenFeign in Spring Boot

📦 Project Structure

com.kscodes.springboot.microservice

├── order-service // Uses Feign to call product-service

└── product-service // Provides product details

⚙️ Step 1: Add Maven Dependencies

In order-service pom.xml:

<groupId>org.springframework.cloud</groupId>

<artifactId>spring-cloud-starter-openfeign</artifactId>

</dependency>

<groupId>org.springframework.cloud</groupId>

<artifactId>spring-cloud-starter-netflix-eureka-client</artifactId>

</dependency>

</dependencies>

Ensure this is in the dependencyManagement:

<groupId>org.springframework.cloud</groupId>

<artifactId>spring-cloud-dependencies</artifactId>

<scope>import</scope>

</dependency>

</dependencies>

</dependencyManagement>

📁 application.yml Configuration

For order-service:

server:

port: 8081

spring:

application:

name: order-service

eureka:

client:

service-url:

defaultZone: http://localhost:8761/eureka

For product-service:

server:

port: 8082

spring:

application:

name: product-service

eureka:

client:

service-url:

defaultZone: http://localhost:8761/eureka

✍️ Step 2: Enable Feign Client

In your OrderServiceApplication class:

package com.kscodes.springboot.microservice.orderservice;

import org.springframework.boot.SpringApplication;

import org.springframework.boot.autoconfigure.SpringBootApplication;

import org.springframework.cloud.openfeign.EnableFeignClients;

@SpringBootApplication

@EnableFeignClients(basePackages = "com.kscodes.springboot.microservice.orderservice.client")

public class OrderServiceApplication {

public static void main(String[] args) {

SpringApplication.run(OrderServiceApplication.class, args);

}

🔗 Step 3: Create the Feign Client Interface

package com.kscodes.springboot.microservice.orderservice.client;

import org.springframework.cloud.openfeign.FeignClient;

import org.springframework.web.bind.annotation.GetMapping;

import org.springframework.web.bind.annotation.PathVariable;

@FeignClient(name = "product-service")

public interface ProductClient {

@GetMapping("/products/{id}")

String getProductById(@PathVariable("id") String id);

}

🧩 Step 4: Use the Feign Client in a Service or Controller

package com.kscodes.springboot.microservice.orderservice.controller;

import com.kscodes.springboot.microservice.orderservice.client.ProductClient;

import org.springframework.web.bind.annotation.GetMapping;

import org.springframework.web.bind.annotation.PathVariable;

import org.springframework.web.bind.annotation.RestController;

@RestController

public class OrderController {

private final ProductClient productClient;

public OrderController(ProductClient productClient) {

this.productClient = productClient;

}

@GetMapping("/orders/{productId}")

public String getOrder(@PathVariable String productId) {

String productInfo = productClient.getProductById(productId);

return "Order placed for: " + productInfo;

}

🧪 Step 5: Create Sample Endpoint in Product-Service

package com.kscodes.springboot.microservice.productservice.controller;

import org.springframework.web.bind.annotation.GetMapping;

import org.springframework.web.bind.annotation.PathVariable;

import org.springframework.web.bind.annotation.RestController;

@RestController

public class ProductController {

@GetMapping("/products/{id}")

public String getProduct(@PathVariable String id) {

return "Product details for ID: " + id;

}

🚀 Step 6: Run and Test

Start Eureka Server
Run product-service on 8082
Run order-service on 8081
Test:

curl http://localhost:8081/orders/123

✅ You should receive:
Order placed for: Product details for ID: 123

🔒 Optional: Add Feign Retry and Timeout Config

feign:

client:

config:

default:

connectTimeout: 3000

readTimeout: 5000

loggerLevel: full

You can also specify retry behavior via Spring Retry.

📈 Benefits of Using OpenFeign Client Communication

✅ Declarative REST clients — clean and concise
✅ Native Spring Boot integration
✅ Works seamlessly with Eureka and LoadBalancer
✅ Reduces boilerplate code
✅ Easier testing and mocking of services

🏁 Conclusion

Using OpenFeign Client Communication in Spring Boot dramatically simplifies inter-service REST calls. With Eureka integration, it enables services to talk to each other with just annotated interfaces, no manual HTTP or URL management needed.

This declarative and elegant approach enhances readability, maintainability, and reduces error-prone boilerplate code — ideal for any production-grade microservice architecture.