What Is API Testing?
API testing involves verifying the API’s functionality, reliability, performance, and security. This type of testing typically involves sending requests to the API and checking the responses to ensure that they match the expected results. API testing can be automated using specialized software tools, which can help to save time and reduce the risk of human error.
Some of the key benefits of API testing include improved quality, reduced development costs, and faster time-to-market. By detecting issues at the earliest stages of the development process, API testing can help to prevent costly errors and delays down the line. Additionally, API testing can help to ensure that the API is secure and meets regulatory compliance requirements.
This is part of a series of articles about application security.
Why Is API Testing Important?
API testing is an important process that offers various benefits to developers, testers, and end-users. Here are some reasons why API testing is important:
- Efficient back-end testing: User interface tests cannot always efficiently validate the functionality of API services and they don’t usually cover all the critical aspects of backend testing. API testing can help identify and fix remaining bugs at the unit or server or level, which can severely delay the product’s release, requiring extensive code rewrites.
- Early testing: Developers can start testing APIs early in the SDLC, before the user interface is consumer-ready. This lets developers catch and fix bugs at the server layer before they are visible at the UI layer, preventing them from becoming more severe. With API testing, testers can make requests that would not be advisable via the UI because they’d expose security flaws.
- Infrastructure for microservices: Many companies are using microservices in their applications, making API testing increasingly crucial for ensuring that all parts of the software are working properly. Each section of an application has separate data stores and there are different commands to interact with these data stores, with most microservices using APIs.
- Enabling agile software development: API testing is integral to agile software development, where instant feedback is necessary to the process flow. In agile environments, unit and API tests are usually better than GUI (graphical user interface) tests because they are more efficient and easier to maintain. GUI testing often requires extensive reworking to keep up with the rapid changes of an agile environment.
9 Types of API Testing
1. Validation Testing
This type of testing ensures that the API is returning the expected results and in the correct format. Validation testing involves checking that the input parameters, output format, response code, and data type are correct.
2. UI Testing
UI testing validates that the API works correctly within the application’s user interface. This type of testing ensures that the UI is accurately reflecting the API’s results and that the API is handling the UI’s inputs correctly.
3. Functional Testing
Functional testing verifies that the API functions correctly and meets the required specifications. This type of testing can include testing the API’s business logic, input validation, output validation, and error handling.
4. Load Testing
Load testing involves testing the API’s performance and stability under stressful conditions. This type of testing simulates high traffic and heavy usage scenarios to ensure that the API can handle a large number of concurrent users and requests.
5. Runtime and Error Detection
This type of testing ensures that the API can handle runtime errors and exceptions. This includes testing for network timeouts, memory leaks, incorrect input parameters, and other errors that can occur during runtime.
6. Penetration Testing
Penetration testing is a type of security testing that involves simulating attacks from hackers to detect vulnerabilities and weaknesses in the API. This type of testing can include network scanning, vulnerability scanning, and manual penetration testing.
7. API Hacking
API hacking is security testing techniques that exploits vulnerabilities in an API. Attackers (and testers) can target API endpoints to gain access to data, disrupt services, or hijack the entire system. Ethical hackers can train by attacking intentionally vulnerable APIs, which can be downloaded from the Internet. Then, they can turn to the organization’s own APIs to test their resilience and find weaknesses.
8. Security Testing
Security testing aims to identify security-related vulnerabilities and flaws in the API and ensure that the API meets the required security standards. This type of testing includes testing for vulnerabilities such as SQL injection, cross-site scripting (XSS), cross-site request forgery (CSRF), and others.
9. Fuzz Testing
Fuzz testing involves feeding unexpected and invalid inputs into the API to test its ability to handle unexpected input and recover from errors. This type of testing can uncover security vulnerabilities or unexpected behavior in the API.
What Are API Testing Tools and Frameworks?
API tools and frameworks are software tools that are designed to help developers build, test, and manage APIs. These tools and frameworks provide a set of functionalities and pre-built components that can help simplify the process of API development and management.
API tools can include software development kits (SDKs), which provide libraries and code samples to help developers integrate with APIs. They can also include software tools for API documentation, testing, and monitoring. API frameworks, on the other hand, provide a structured approach to building and managing APIs. They include pre-built components, such as authentication and authorization mechanisms, data validation, and error handling, that can be used to create consistent and reliable APIs.
API Testing Best Practices
Here are some best practices to follow when conducting API testing:
Automate Your API Tests
Automating your API tests involves using specialized software tools to create and execute your API tests automatically. Automated testing tools can help you create test scripts, run tests, and generate test reports more efficiently than manual testing. Additionally, automated testing can help you test your API more thoroughly and identify bugs or issues that may be missed with manual testing.
Run Tests Throughout the API Lifecycle
Testing your API throughout the entire lifecycle, from development to deployment, can help you catch issues early and ensure that the API works correctly in different environments. Testing during the development phase can help catch issues before they become more significant problems and reduce the risk of errors in the final product. Additionally, testing in different environments can help ensure that the API is working correctly in each environment.
Write Reusable Subtests
Writing reusable subtests involves creating modular test scripts that can be reused for multiple APIs. Creating reusable subtests can help you save time and improve efficiency by eliminating the need to write new tests for each API. Additionally, writing reusable subtests can help ensure that tests are consistent across different APIs, making it easier to compare results and identify issues.
Keep Your Tests Organized
Organizing your tests can help you manage your test suites more efficiently and make it easier to identify and fix issues. Some ways to organize your tests include grouping tests by function, endpoint, or test type. Additionally, creating naming conventions for your tests can help you quickly identify and locate specific tests.
API Security with Imperva
Imperva provides an API Security solution, which automates API protection to ensure API endpoints are protected as they are published, shielding your applications from exploitation.
Beyond API security, Imperva provides comprehensive protection for applications, APIs, and microservices:
Web Application Firewall – Prevent attacks with world-class analysis of web traffic to your applications.
Runtime Application Self-Protection (RASP) – Real-time attack detection and prevention from your application runtime environment goes wherever your applications go. Stop external attacks and injections and reduce your vulnerability backlog.
Advanced Bot Protection – Prevent business logic attacks from all access points – websites, mobile apps and APIs. Gain seamless visibility and control over bot traffic to stop online fraud through account takeover or competitive price scraping.
DDoS Protection – Block attack traffic at the edge to ensure business continuity with guaranteed uptime and no performance impact. Secure your on premises or cloud-based assets – whether you’re hosted in AWS, Microsoft Azure, or Google Public Cloud.
Attack Analytics – Ensures complete visibility with machine learning and domain expertise across the application security stack to reveal patterns in the noise and detect application attacks, enabling you to isolate and prevent attack campaigns.
Client-Side Protection – Gain visibility and control over third-party JavaScript code to reduce the risk of supply chain fraud, prevent data breaches, and client-side attacks.
