Introduction to API Testing — Reconnaissance

API testing has become an integral part of ensuring the security and functionality of modern applications. However, before diving into the testing phase, it’s crucial to conduct thorough API reconnaissance. In this blog post, we’ll explore the essential steps in API recon and how to leverage documentation, both human-readable and machine-readable, to maximize the effectiveness of your API testing efforts.

Identifying API Endpoints

The first step in API recon is to identify the API endpoints. These endpoints represent the locations where the API processes requests related to specific resources. For example, a GET request to “/api/books” retrieves a list of books from a library. Understanding these endpoints is critical for constructing valid HTTP requests during testing.

Understanding API Interaction

Once the endpoints are identified, the next step is to understand how to interact with them. This involves gathering information about the input data the API processes, including mandatory and optional parameters, supported HTTP methods, media formats, rate limits, and authentication mechanisms. This knowledge allows testers to construct meaningful test cases and ensure comprehensive coverage.

Leveraging API Documentation

API documentation serves as a valuable resource for understanding how an API works. Whether it’s in human-readable or machine-readable form, documentation provides crucial insights for both developers and testers.

a. Human-Readable Documentation:

Human-readable documentation is designed for developers to understand the API’s functionality, with detailed explanations, examples, and usage scenarios. Always start your API recon by reviewing publicly available documentation to gain insights into the API’s intended usage.

b. Machine-Readable Documentation:

Machine-readable documentation, often in JSON or XML format, is designed for automation. Even if the documentation is not openly available, testers can leverage tools like Burp Scanner to crawl the API and identify potential documentation endpoints, such as…