How to Add Request and Response Interceptors to OpenFeign with OkHttp in Spring Cloud

Spring Cloud's OpenFeign uses OpenFeign for inter-service calls, which by default relies on javax.net.ssl.HttpsURLConnection that lacks interceptor and connection pool support.

To enable interceptors, replace the default client with a third‑party HTTP client such as HttpClient or OkHttp. The Maven dependencies are:

<dependency>
  <groupId>io.github.openfeign</groupId>
  <artifactId>feign-httpclient</artifactId>
  <version>9.7.0</version>
</dependency>
<dependency>
  <groupId>io.github.openfeign</groupId>
  <artifactId>feign-okhttp</artifactId>
  <version>9.7.0</version>
</dependency>

Then disable the default HttpClient and enable OkHttp in application.properties :

feign.httpclient.enabled=false
feign.okhttp.enabled=true

For request interception, implement feign.RequestInterceptor and register it as a Spring component:

@Component
public class CustomerFeignRequestInterceptor implements RequestInterceptor {
    @Override
    public void apply(RequestTemplate template) {
        ServletRequestAttributes attributes = (ServletRequestAttributes) RequestContextHolder.getRequestAttributes();
        if (attributes != null) {
            HttpServletRequest request = attributes.getRequest();
            template.header("sessionId", request.getHeader("sessionId"));
        }
    }
}

Response interception can be achieved by customizing the OkHttp client. Define a bean that returns an OkHttpClient.Builder with a response interceptor:

@Configuration
public class FeignOkHttpClientConfig {
    @Bean
    public OkHttpClient.Builder okHttpClientBuilder() {
        return new OkHttpClient.Builder().addInterceptor(new FeignOkHttpClientResponseInterceptor());
    }

    public static class FeignOkHttpClientResponseInterceptor implements Interceptor {
        @Override
        public Response intercept(Chain chain) throws IOException {
            Request originalRequest = chain.request();
            Response response = chain.proceed(originalRequest);
            MediaType mediaType = response.body().contentType();
            String content = response.body().string();
            // process content as needed
            return response.newBuilder()
                    .body(ResponseBody.create(mediaType, content))
                    .build();
        }
    }
}

By customizing the OkHttpClient.Builder , you can add any response interceptor without recreating the entire OkHttpClient , avoiding the fallback to Feign's circuit‑breaker behavior.

In summary, switching to OkHttp, adding a request interceptor, and providing a response interceptor via a custom builder solves the interceptor limitation in Spring Cloud OpenFeign.