Guides

REST API testing

Complete guide to REST API testing with HITOP. Learn how to test RESTful APIs, validate responses, and automate API workflows.

What is REST API testing?

REST API testing is the process of validating RESTful web services to ensure they function correctly, return expected responses, and handle errors appropriately. It involves sending HTTP requests to API endpoints and verifying the responses.

Understanding REST APIs

REST (Representational State Transfer) is an architectural style for designing networked applications. RESTful APIs use HTTP methods to perform operations on resources:

Why test REST APIs?

REST API testing is crucial for:

REST API testing with HITOP

HITOP provides a comprehensive environment for testing REST APIs with features designed specifically for RESTful services.

Testing GET requests

GET requests retrieve data from the server. With HITOP, you can:

GET https://api.example.com/users/123
Headers:
  Authorization: Bearer your-token-here
  Accept: application/json

Testing POST requests

POST requests create new resources. HITOP supports JSON, form data, and raw body formats:

POST https://api.example.com/users
Headers:
  Content-Type: application/json
  Authorization: Bearer your-token-here
Body:
{
  "name": "John Doe",
  "email": "john@example.com"
}

You can leave the Content-Type header out: when a POST, PUT or PATCH body has none, HITOP sends application/json for a body that starts with { or [, text/html for an HTML page, application/xml for other <...> and text/plain for anything else. The CLI, the MCP server, the web app, the desktop app and the iOS companion all do it the same way, hitop snippet shows the header, and it is never written into your collection. A header of your own always wins. A URL typed without a scheme, such as api.example.com/users, is sent as https://api.example.com/users (http:// for localhost and 127.0.0.1).

Testing PUT and PATCH requests

Update existing resources with PUT (full update) or PATCH (partial update):

PATCH https://api.example.com/users/123
Headers:
  Content-Type: application/json
Body:
{
  "email": "newemail@example.com"
}

Testing DELETE requests

Remove resources from the server:

DELETE https://api.example.com/users/123
Headers:
  Authorization: Bearer your-token-here

Key aspects of REST API testing

1. Status code validation

Verify the API returns appropriate HTTP status codes:

2. Response body validation

Check that the response contains expected data structure and values. HITOP's syntax highlighting makes it easy to inspect JSON responses.

3. Header validation

Verify response headers including Content-Type, Cache-Control, and custom headers.

4. Authentication testing

Test various authentication methods:

Advanced REST API testing

Collection variables

Use collection variables to switch the server or user in one place:

${base_url}/users/${user_id}

Variables:
  base_url: https://api.staging.example.com
  user_id: 123

Script before

In the Script before tab, run JavaScript before the request is sent to set up authentication, generate timestamps, or modify request data.

Script after

In the Script after tab, validate responses, extract data for subsequent requests, or perform assertions.

Collection runner

Run multiple API tests sequentially to test complete workflows:

  1. Create user (POST)
  2. Retrieve user (GET)
  3. Update user (PATCH)
  4. Delete user (DELETE)

Best practice

Organize your REST API tests into collections by resource or feature. This makes it easy to run related tests together and share with team members.

Common REST API testing scenarios

CRUD operations testing

Test Create, Read, Update, Delete operations for each resource in your API.

Query parameters

Test filtering, sorting, and pagination:

GET https://api.example.com/users?page=2&limit=10&sort=name

Error handling

Verify your API handles errors gracefully:

Edge cases

Test boundary conditions, empty responses, large payloads, and special characters.

REST API testing checklist

Why use HITOP for REST API testing?

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