Introduction

Imagine you walk into a massive library looking for a specific book on “Ancient History.” If the books are piled in random heaps on the floor with no labels, you’ll spend hours frustrated and likely leave empty-handed. But if the library uses a standardized system — labeled aisles, alphabetical order, and clear categories — you find your book in seconds.

In the world of software, API management is that library system. Specifically, Apigee X acts as the professional librarian. It doesn’t just store your data; it organizes, secures, and presents it to the world in a way that makes sense.

The main topic we are diving into today is REST API Design. By following “RESTful” best practices, you ensure that any developer in the world can look at your API and understand exactly how to use it without reading a 500-page manual. In this post, we’ll cover the golden rules of URL structure, HTTP methods, and how to use Apigee X to enforce these standards across your enterprise.

Core Concepts: The Pillars of RESTful Design
When we talk about API proxies in Apigee X, we are talking about a “facade.” You might have a messy, old backend database, but your Apigee proxy should look like a clean, modern storefront.

1. Nouns, Not Verbs

In a RESTful world, everything is a “Resource.” Think of resources as things you can touch, like customers, orders, or products.

Analogy: Your URL should be the “Address” of the house, not the “Action” of moving in.
Incorrect: GET /getAllOrders or POST /createOrder
Correct: GET /orders or POST /orders

2. The Power of HTTP Verbs

Instead of putting the action in the URL, we use the standard HTTP methods to tell the server what to do.

GET: Read a resource.

POST: Create a new resource.

PUT/PATCH: Update an existing resource.

DELETE: Remove a resource.

3. Predictable Nesting

If you want to find the orders for a specific customer, your URL should follow a logical hierarchy.

Example: /customers/521/orders (This clearly says: "Give me the orders belonging to customer 521").

Step-by-Step Guide: Designing a “Clean” Proxy in Apigee X
Let’s build a professional “Products” API proxy. We will use Apigee to map a clean RESTful URL to a backend service.

1. Define the OpenAPI Specification (OAS)
The best practice is to start with a design. In the Apigee UI, go to Design > Spec and define your paths.

# A snippet of a clean REST definition
paths:
  /products:
    get:
      summary: List all products
    post:
      summary: Add a new product
  /products/{productId}:
    get:
      summary: Get details for a specific product

2. Create the Proxy using the Wizard

Select Create Proxy -> Reverse Proxy.
Base Path: Use /v1/shipping/products.
Target Endpoint: Point this to your backend service (e.g., https://mocktarget.apigee.net).

3. Enforce Content-Type (Example Policy)

A REST best practice is to always respond with JSON. We can use an AssignMessage policy in the response flow to ensure the Content-Type is always correct.

<AssignMessage name="AM-SetJSONHeader">
    <Set>
        <Headers>
            <Header name="Content-Type">application/json</Header>
        </Headers>
    </Set>
    <IgnoreUnresolvedVariables>true</IgnoreUnresolvedVariables>
</AssignMessage>

Invoke your API with curl:

# Request
curl -X GET "https://your-apigee-host/v1/shipping/products/123"
Expected Response
{
“id”: “123”,
“name”: “Wireless Mouse”,
“status”: “in-stock”
}

Best Practices for API Management

1. Version Your APIs: Always start your base path with a version number (e.g., /v1/). This allows you to upgrade your API logic in the future without breaking the apps currently using it.

2. Use Plural Nouns: Use /users instead of /user. It makes it clear that the base path represents a collection of items.

3. Return Standard Status Codes: * 201 Created for a successful POST.
   404 Not Found if the resource doesn’t exist.

429 Too Many Requests for API traffic management when a user hits a rate limit.

1. Filter, Don’t Nest: For complex queries, use query parameters instead of long paths.

• Bad: /products/electronics/laptops/brand/apple
• Good: /products?category=laptops&brand=apple

Common Mistake: Trying to mirror your database structure exactly. Your API should represent your business logic, not your table names. This keeps your API security higher by hiding internal details.

Conclusion
Designing a RESTful API is like writing a good book — consistency and clarity are everything. By using nouns, leveraging HTTP verbs, and managing everything through Apigee X, you create an ecosystem where developers can thrive.

Don’t just build an API that works; build an API that people love to use!

Call to Action
What’s the most confusing API URL you’ve ever had to work with? Share your “API horror stories” in the comments! If you want to dive deeper into API proxies or API security, subscribe to our blog or follow us on social media for more weekly Apigee X masterclasses.