APIs power the modern web. From mobile apps to single-page applications, almost every software today depends on APIs to communicate and exchange data. Among them, REST APIs are the most widely used because of their simplicity and compatibility with HTTP.
In this article, we will take a clear and simple look at REST API methods and discuss best practices that help you build clean, secure, and scalable APIs.
Let’s get started.
REST (Representational State Transfer) is a set of rules and principles for designing networked applications. REST APIs work over HTTP and use standard HTTP methods to perform actions on resources. In simple terms, a REST API allows different systems to communicate over the web using URLs, HTTP methods, and JSON for exchanging data.
If you have built or consumed a web application, you are likely already using REST APIs without realizing it.
HTTP methods define what action you want to perform on a resource. Let’s go through each of them.
GET is used to fetch data from the server. It does not change anything on the server. It is read-only and safe.
Example:
GET /api/v1/users
This will return the list of users.
When to use:
POST is used to create a new resource. The data you send in the request body is used to create something new on the server.
Example:
POST /api/v1/users
Request body:
{
"name": "John Doe",
"email": "john@example.com"
}
This will create a new user.
When to use:
PUT is used to replace the entire resource with new data. However, in many real-world APIs, PUT may also be used to partially update data, similar to PATCH. Still, the original intention of PUT is to replace the full resource.
Example:
PUT /api/v1/users/123
Request body:
{
"name": "Updated Name",
"email": "updated@example.com"
}
This will replace the user with ID 123 with the new data.
When to use:
PATCH is used to update only specific fields in a resource. It does not replace the entire resource.
Example:
PATCH /api/v1/users/123
Request body:
{
"email": "newemail@example.com"
}
This will only update the email of user 123.
When to use:
PATCH requests are usually not idempotent by default. Whether they are or not depends on how you design the API.
DELETE is used to remove a resource from the server.
Example:
DELETE /api/v1/users/123
This will delete the user with ID 123.
When to use:
Idempotency means performing the same operation multiple times will produce the same result.
Idempotency makes your API predictable and reliable, especially when dealing with network retries.
Using correct HTTP methods is just the start. To make your API clean and easy to use, you should also follow these best practices.
Keep your API URLs meaningful and resource-oriented.
Good example:
/api/v1/users
/api/v1/users/123
Avoid:
/api/v1/doAction
/api/v1/getUserData
Do not use verbs in URLs. HTTP methods already indicate the action.
Always version your API, especially if it is public or shared with other developers.
Example:
/api/v1/users
Versioning allows you to make changes later without breaking old clients.
Return proper status codes to indicate the result of the request.
These codes help API consumers handle responses correctly.
Your API responses should follow a predictable structure.
Example for success:
{
"status": "success",
"data": { }
}
Example for errors:
{
"status": "error",
"message": "Email is required."
}
This makes parsing and debugging easy for developers.
Never trust incoming data. Always validate and sanitize inputs to:
Reject requests with invalid or missing data.
Protect sensitive endpoints.
Unprotected APIs are a security risk.
Do not return huge lists in a single response. Use pagination.
Example:
/api/v1/users?page=2&per_page=20
Also allow filtering and sorting for flexible data fetching.
Prevent abuse and DDoS attacks by limiting the number of requests.
Rate limiting can be implemented at the API gateway, load balancer, or server level.
If limit is exceeded, return:
429 Too Many Requests
Rate limiting keeps your API healthy and available.
Always send clear and helpful error messages.
Avoid this:
{ "error": "Something went wrong" }
Instead, send this:
{
"status": "error",
"message": "Invalid user ID"
}
Good error messages save developers hours of debugging.
Implement caching to improve performance.
Caching reduces server load and improves speed.
Security should never be compromised.
APIs consumed by browsers must handle CORS properly.
Proper CORS configuration ensures secure cross-domain communication.
Always log:
Logs help in debugging and improve reliability.
Good APIs are easy to use. Document your API properly.
Documentation reduces support requests and makes onboarding easier.
Do not break old APIs suddenly.
Smooth transitions make your API reliable for long-term use.
REST APIs are simple but powerful. When designed properly, they make your application easy to integrate and extend. Understanding the correct usage of HTTP methods and following best practices ensures that your API is secure, reliable, and developer-friendly.
Whether you are building a public API or an internal service, applying these principles from the start will save you time and trouble in the future. A well-designed API is not only easy to use but also easy to maintain and scale.
If you are building your next API, make sure to use these guidelines as your checklist. It will make a huge difference in the quality of your project.
If you found this article interesting, found errors, or just want to discuss about them, please get in touch.