API Gateway & Reverse Proxy (Nginx + Spring Cloud Gateway) · Lesson

Setting Up a Basic Gateway Project

Initialize a Spring Boot project with Spring Cloud Gateway and configure a simple working gateway.

Setting Up a Basic Gateway Project is a free API Gateway & Reverse Proxy (Nginx + Spring Cloud Gateway) lesson on CoddyKit — lesson 2 of 4. You can read the complete lesson below for free — then practise it hands-on in the browser with a built-in code editor and a 24/7 AI tutor. It is part of the API Gateway & Reverse Proxy (Nginx + Spring Cloud Gateway) learning path, one of 4 lessons in the course, and your progress syncs across the web and the CoddyKit app.

Gateway Project Setup

Welcome! In this lesson, you'll learn how to initialize a basic Spring Cloud Gateway project. This is your first step to building powerful API gateways.

We'll cover setting up the necessary dependencies and creating a minimal working gateway configuration.

What You'll Need

Before we dive in, ensure you have the following tools installed:

Java Development Kit (JDK) 17+: For running Spring Boot applications.
Maven or Gradle: Build automation tools for managing project dependencies.
An IDE (e.g., IntelliJ IDEA, VS Code): For writing and managing your code.

These are standard for Spring Boot development.

Start with Spring Initializr

The easiest way to start any Spring Boot project is with Spring Initializr. It helps you generate a project with all the necessary setup.

For our gateway, you'll select specific dependencies to get started quickly.

Key Gateway Dependencies

When using Spring Initializr, search for and add these key dependencies:

Spring Cloud Gateway: This is the core library that provides gateway functionality.
Spring WebFlux: Gateway is built on reactive programming, so WebFlux is a transitive dependency and crucial for its operation.

Choose your preferred build tool (Maven or Gradle) and Java version (e.g., 17 or 21).

The Main Application Class

After generating and importing your project, you'll find a main application class. This class uses @SpringBootApplication to bootstrap your application.

Run this simple Spring Boot application to see it start up. It won't do much yet, but it's alive!

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

@SpringBootApplication
public class GatewayProjectApplication {

  public static void main(String[] args) {
    SpringApplication.run(GatewayProjectApplication.class, args);
  }
}

Configuring Gateway Routes

Now that our application can run, we need to tell the gateway what to do! This is done by defining routes in your application.yml (or application.properties) file.

A route maps incoming requests to a specific backend service based on certain conditions.

Basic Route Example

Let's add a simple route to src/main/resources/application.yml. This route will forward requests from /get to http://httpbin.org:80, a public testing service.

This is your first step to proxying requests!

spring:
  cloud:
    gateway:
      routes:
        - id: httpbin_route
          uri: http://httpbin.org:80
          predicates:
            - Path=/get

Understanding the Route

Let's break down that route configuration:

id: httpbin_route: A unique identifier for this route.
uri: http://httpbin.org:80: The target backend service URL where requests will be forwarded.
predicates: - Path=/get: A condition that must be met for this route to activate. Here, it means any request with a path starting with /get.

Predicates are like 'if' statements for routing.

Running & Testing Your Gateway

With the application.yml updated, restart your Spring Boot application. The gateway will now pick up the new route.

You can test it using curl or your web browser:

Open your terminal.
Run: curl http://localhost:8080/get

You should see a JSON response from httpbin.org, proving your gateway is working!

Gateway Setup Check

You've just set up your first Spring Cloud Gateway project!

Which of the following is the primary dependency required to enable Spring Cloud Gateway functionality in a Spring Boot project?

Recap: Basic Gateway Setup

Great job! You've learned how to:

Initialize a Spring Boot project using Spring Initializr.
Add the essential spring-cloud-starter-gateway dependency.
Create a basic Spring Cloud Gateway application class.
Configure your first gateway route in application.yml.
Test your gateway to ensure it's forwarding requests correctly.

This foundational knowledge will help you build more complex gateway configurations in future lessons!

Frequently asked questions

Is the “Setting Up a Basic Gateway Project” lesson free?

Yes — the full text of “Setting Up a Basic Gateway Project” is free to read here on the web, and the API Gateway & Reverse Proxy (Nginx + Spring Cloud Gateway) course includes 4 lessons in total. To practise it interactively (a built-in code editor and a 24/7 AI tutor) and unlock the rest of the API Gateway & Reverse Proxy (Nginx + Spring Cloud Gateway) course, upgrade to CoddyKit PRO.

What will I learn in “Setting Up a Basic Gateway Project”?

Initialize a Spring Boot project with Spring Cloud Gateway and configure a simple working gateway. You practise API Gateway & Reverse Proxy (Nginx + Spring Cloud Gateway) with hands-on code you run directly in the browser, and a 24/7 AI tutor answers your questions as you work through the lesson.

Do I need any experience to start API Gateway & Reverse Proxy (Nginx + Spring Cloud Gateway)?

No prior experience is required. API Gateway & Reverse Proxy (Nginx + Spring Cloud Gateway) on CoddyKit is structured for beginners through advanced learners; this is — lesson 2 of 4, so you can start here or from the beginning and move at your own pace.

How long does the “Setting Up a Basic Gateway Project” lesson take?

Most CoddyKit lessons take about 5–10 minutes. Each one is bite-sized and interactive, so you make steady progress and pick up exactly where you left off across the web and the app.

Can I write and run code in this API Gateway & Reverse Proxy (Nginx + Spring Cloud Gateway) lesson?

Yes. Every API Gateway & Reverse Proxy (Nginx + Spring Cloud Gateway) lesson includes a built-in code editor, so you write and run real code right in your browser and get instant AI feedback — no local setup required.

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