Automated API Testing Services

The primary goal of API testing is going beyond manual testing by executing code-level testing of an application and the APIs supporting it. Strong API testing practices can ensure the security of the application’s code and confirm the expected interaction between the API layer and the application.

What Is API Testing?

APIs, or Application Programming Interfaces, are what developers use to connect one application to another which allows for data exchanges between pieces of software. If an API doesn’t work efficiently or effectively, it can negatively impact software quality, business processes and the end user’s experience.

Most applications include three primary layers - the user interface (presentation), the business layer and the database which is used to categorize and manipulate the data.

QASource’s API Testing Services Include

A strong API testing process should include the types of tests highlighted below to ensure that all API performance, functionality and security features are in place. Our team at QASource also implements automated testing techniques to increase the efficiency and comprehension of API tests.

Functional Testing

Allow time for functional testing so you can properly validate the end to end functionality of your application and API layers.

Web UI Testing

This type of testing involves the graphical user interface and makes sure that the web application or website’s functionality and usability meet expectations.

Load Testing

Make sure the application and APIs perform as they should when under heavy number of users.

Runtime/Error Detection

This type of testing ensures that all exceptions and resource leaks are identified and corrected.

Security Testing

Ensure that common security features like authentication, permission settings and access controls meet the predefined requirements. Common security testing approaches include penetration and fuzz testing.

Validation Testing

Validation testing is one of the last types of testing that teams complete and ensures that API connections are working properly across the application. Validation testing typically includes a series of smaller tests which include unit, integration, system and UAT Testing.

Interoperability and WS Compliance Testing

Make sure that your SOAP APIs communicate correctly and efficiently with all other software components.

Automated API Testing

Having a team and technology in place that can automate a percentage of the tests, allow teams to scale quickly and ensure their APIs receive comprehensive testing.

API Testing Benefits

Ease of Access

API Testers can detect and correct errors earlier before they become larger issues.


Because API testing requires less coding, your team can enjoy faster test results more affordably.

Increased Security

The unique set of conditions and inputs within an API removes common vulnerabilities and adds more protection for an application.

Language Independent

An API test exchanges data using XML or JSON. These transfer modes are completely language-independent, meaning that you can select any core language when pursuing automated testing services for your application.

Simple Integration With GUI

Web API testing supports highly integrable tests, which are especially beneficial when your team executes functional GUI tests following your API testing process.

Less Time Consuming Than Functional GUI Testing

API testing allows teams to scale quickly and efficiently. Our team of experts project that 3,000 API tests can be completed in about 50 minutes, while 3,000 functional GUI tests will take approximately 50 hours.

Our API Testing Tools Include

There are a variety of API testing tools available to development and QA teams, but selecting the best set of tools can be a time consuming and difficult process. When you partner with QASource, our team of tool agnostic experts can help your team evaluate, choose and implement the most appropriate set of tools to complete your API testing needs.

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Frequently Asked Questions

What is API testing?

API testing is validating the functionality, performance, reliability, and security of an application programming interface (API). APIs act as intermediaries, allowing different software components to communicate and exchange data. API Testing ensures these interactions occur smoothly and as intended. Unlike UI testing, API testing does not focus on the look and feel of an application but on its business layer.

Why is API testing important?

APIs are critical for connecting and transferring data between systems or applications. API testing ensures the connections are reliable, secure, and perform as expected. This type of testing can identify issues early in the development cycle, improving the quality of the final product and save time and resources.

What types of API testing does QASource offer?

QASource services cover a comprehensive range of API testing, including functionality testing, reliability testing, performance testing, and security testing. We employ both automated and manual testing techniques to ensure a thorough evaluation of the APIs.

How does API testing integrate with Agile and DevOps practices?

API testing is essential for Agile and DevOps environments, promoting continuous testing and integration. Our API testing services are designed to seamlessly integrate with these practices, ensuring continuous delivery and deployment without compromising quality.

Can API testing be automated?

Yes, a significant portion of API testing can be automated, and it is highly recommended. Automated API testing facilitates more frequent and thorough tests, contributing to faster development cycles and more reliable software. Our team specializes in implementing and maintaining automated API testing frameworks tailored to your needs.

How is API testing different from UI testing?

API testing delves into the application's inner workings, focusing on how the building blocks (APIs) communicate and exchange data. On the other hand, UI testing concentrates on the user experience, evaluating how users interact with the application's surface (UI), such as buttons, menus, and visuals. API testing ensures the application's core functions operate correctly, while UI testing verifies that users can interact with them seamlessly.

What are the challenges of API testing?

APIs can be complex, with multiple endpoints, methods, parameters, and data formats, making thoroughly testing all possible scenarios challenging. APIs often support various data formats like JSON, XML, or YAML. Testing with different data formats requires careful validation to ensure compatibility and correctness. Our team specializes in handling these challenges and delivering robust results.

What is the difference between unit testing and API testing?

Unit testing and API testing serve distinct purposes in software testing. Unit testing evaluates individual units or components in isolation, ensuring they function correctly according to specifications. In contrast, API testing focuses on validating the behavior and functionality of APIs exposed by the software. It tests the integration between various components through API calls, verifying inputs, outputs, and interactions.

How do you handle authentication in API testing?

Authentication in API testing can be handled using techniques such as providing API keys, OAuth tokens, or username/password credentials in the request headers or as query parameters.

How do you ensure API reliability in testing?

To ensure API reliability in testing, testers can perform functional testing to validate the correctness of API responses, performance testing to assess the responsiveness and scalability of APIs under various loads, and security testing to identify and mitigate potential vulnerabilities. Additionally, testers can implement automated testing and continuous integration practices to detect regressions early in development. Our team is proficient in the tools and techniques used in API testing.