Building microservices is a powerful approach, but interacting with external APIs often becomes repetitive. Developers using RestTemplate must write code for every step, from building URLs to handling responses, leading to a slow process that is error-prone and, frankly, frustrating. Fortunately, there is a better way to handle this problem and help developers manage large amounts of API calls—using the Feign Client in Spring Boot. This blog will explain how the Feign Client in microservices streamlines Spring Boot API interactions.

What is Spring cloud Feign Client?

Feign Client is a tool for developers, especially those using Java with Spring Boot. It simplifies creating connections to web services by letting you define an interface. Imagine having a to-do list app and needing to communicate with a separate service for user accounts. With Feign, users design an interface outlining how to interact with the user service. Feign handles behind-the-scenes communication, such as sending requests and processing responses, freeing developers to focus on the core logic of their applications. Feign is like a translator that speaks the language of web services, allowing apps to communicate with them easily.

Dependency for Feign Client

Steps to configure the Feign Client

Step 1: Enable the Feign Client inside the main class using @EnableFeign Clientsannotation and import the Feign auto-configuration annotation. ‘@ImportAutoConfiguration({Feign AutoConfiguration.class})’.

Step 2. Create an interface inside the project that will act as the client for this API, c. Add URLs that need to be called from third-party services.

Step 3: To handle custom error response, use the Error Decoder and custom exception.

Step 4: Configure the bean creation of Feign CustomErrorDecoder.class

Step 5: Consume this API in the service class by auto-wiring the above interface.

Step 6: Create one rest controller for consuming the above service class.

Testing with postman

Start by making a GET request to retrieve book information from our API. Use the following endpoint as an example:

locahost:8080/book.

Third-party API that is being consumed:

Advantages of Spring Boot Feign Client

• Clean and concise Interactions: The Feign Client for Spring Boot lets you define API interactions through annotated interfaces, making your code more readable and easier to maintain.
• Built-in load balancing: Forget about managing complex load-balancing logic. The Spring Feign Client integrates with tools like Ribbon to automatically distribute requests across available services.
• Effortless cross-cutting concerns: Feign allows you to define interceptors for tasks like logging, authentication, and request processing. This keeps your core logic clean and avoids code duplication. 
• Seamless spring integration: Feign plays nicely with other Spring Cloud components like Spring Cloud Config and Spring Cloud Hystrix, simplifying development within the Spring ecosystem.

Feign Client in Spring Boot transforms microservice development. Forget tedious API interactions – define clear interfaces and let Feign handle the legwork. Built-in features like load balancing and error handling elevate your code's efficiency and resilience. Embrace Feign Client to streamline development, write cleaner code, and build robust microservices with ease. Write to us at contact@opcito.com and we’ll help you with Feign Client implementation in Spring Boot.