Top 10 API Testing Types Every Tester Should Know

17Jun, 2024

Creating a successful app requires careful consideration of software testing. Additionally, you will ultimately come across the idea of API testing, which software engineers and QA teams actively apply. According to statistics, nearly 90% of developers utilize APIs in some way. Initial software issue detection throughout the development cycle might assist in avoiding more serious difficulties later on. This is made possible via API testing.

Do you know what is API testing? Additionally, it guarantees APIs’ seamless connection with other software elements, fostering effective data interchange and system integration. Finally, by verifying the capabilities and efficiency of the API, API testing improves the overall performance and layout of the product.

In the current digital world, systems are linked and complicated, and API testing is a crucial activity that improves the performance, stability, and compatibility of software applications. In addition to improving user experience, this lowers the possibility of significant errors occurring during the manufacturing phase. Before you hire an API testing service, make sure you know everything. Read the following blog to understand why API testing is necessary and what are the common API testing types.

What is API Testing?

Software testing that focuses on confirming whether APIs live up to expectations in terms of efficiency, speed, safety, and dependability is known as API testing. Requests are sent to API endpoints, and the procedure includes examining the answers to see if they function as anticipated. API testing works directly with the app’s logic layer, in contrast to typical software testing, which may contain user interface and user experience tests. By testing at this stage, problems may be found and fixed early in the building cycle, enhancing the application’s dependability and quality.

Have you cleared your doubts regarding what is API testing? The testing is crucial to maintaining this functionality. It aids in keeping an eye on the programming interface’s reliability, privacy, and performance. Since when one interface fails, the entire service is rendered useless, API testing also aids in determining whether the interface is living up to expectations. API testing is the procedure that most effectively exposes errors or discrepancies in a program or application. When carried out regularly, it may assist in creating a product that is unlikely to malfunction.

It is possible to run a variety of tests to make sure the API is functioning properly. These tests help find mistakes and problems, eliminating any redundant or missing features, problems with performance, security, and reliability, as well as problems with incorrect handling of parameters or arguments. Therefore, it’s tougher to verify that the API is utilizing resources appropriately and as planned. Some of these tests will probably be considered standard for the normal web API development lifecycle. Find what are the common API testing types, by scrolling down!

Also Read: How To Test Salesforce Performance Using JMeter in 2024?

Why is API Testing Important?

API testing is a crucial step that delivers perks to developers, testers, and end-users. Read the reasons why the API testing approach is necessary –

  • Back-end testing: The UI tests can’t always validate the API functionality efficiently and do not cover the crucial aspects of back-end testing. API testing helps to evaluate & fix the existing bugs that can delay the release time of a product and need code rewriting.
  • Early testing: the programmers can initiate testing APIs early in the SDLC before the user interface being consumer-ready. It allows developers to catch & fix errors at the server layer before it begins to be visible in the UI layer. It prevents them from becoming severe. With API testing, the testing team can make requests that won’t be advised.
  • Developing agile software: API testing is essential to agile software development since frequent and quick feedback is required during the process flow. In the agile environment, API and Unit tests are better than the GUI tests since they are more efficient & easier to maintain.
  • Microservices infrastructure: A wide number of businesses are utilizing microservices in their business operation. It makes the API testing crucial to verify that every software component is working perfectly.
  • Quicker Bug Repairs: Since API testing produces findings rapidly, you may immediately determine if the outcomes are favorable or unfavorable. This can assist you in identifying issues early in the system’s development process, enabling effective bug finding and elimination.
  • Lower Testing Expenses: The expenses of testing are greatly reduced since API testing covers more land, is simpler to operate, and yields findings quickly.
  • Security concerns: With API testing, we can also use a specific set of variables that resemble the potential methods of phishing attempts to search for security gaps. Are you aware of when to conduct the testing? The response will come as soon as it can. Shift-left security includes API security testing, and developers should find and fix security flaws before releasing them into production. After an application is put into production, security vulnerabilities might grow more serious, and late API testing could be costly.
  • Faster Release: It’s common knowledge that GUI testing takes longer to deliver goods. But API testing turns out to be the quicker fix, saving you as much as hours of work. As a result, you have a wonderful chance to concentrate on other essential facets of software development.
  • More Comprehensive Test Coverage: It is preferable to examine an automobile’s construction quality within rather than outside. Automation API testing checks if databases are successfully talking with each other at the level beneath the user interface. In the end, greater emphasis simply means that all of the system’s components are examined at once. Additionally, increased test coverage results in higher-quality products and happier users.


What Are the Different Types of API Testing?

One of the most crucial parts of contemporary development is application programming interfaces (APIs), which act as the links between apps to provide services and transmit data. There is still considerable misunderstanding regarding the kinds of APIs that are most appropriate for certain applications, even though developers and C-suite executives are beginning to take APIs into account earlier in the development lifecycle.


Every type of API testing has a unique architecture that was developed to satisfy the needs of the era. Additionally, as technology has advanced and our connection with it has changed, APIs have emerged to cover new ground and have a variety of purposes.

We’ll go over the different types of API testing in this blog, along with the other things to keep in mind. For more knowledge, hire the software testing outsourcing team.

1. Validation Testing

These types of API testing are often carried out at the final stage of the SDLC. Validation testing looks at things like code bloat, API behavior, and whether API is suitable for the application. It also assesses the program’s correctness, effectiveness, and degree of optimization.

  • When validation testing is essential

Validation tests ensure the product satisfies and conforms to consumer tastes, needs, and expectations in a variety of scenarios (such as poor battery life or delayed connectivity). Such tests are also necessary to guarantee that the program runs without a hitch on various browser-device-OS combinations.

2. Functional Testing

To make sure the API does the intended tasks successfully, functional tests look at the API’s business logic. To test every feature of the API and ensure that it operates as expected under diverse circumstances, testers construct a variety of scenarios. This involves evaluating every possible combination of inputs and considering outputs that were desired. Functional testing assists in discovering errors in the specified business logic by verifying the API operates appropriately in a variety of scenarios. This makes it easier to assess how well the API can manage expected tasks in practical use situations.

  • When functional testing is essential

This is crucial to verify quality & functions. Using this kind of software testing, quality control teams make sure the system operates by user demands and validate the product’s functionality. This testing technique is mostly used to evaluate accessibility capabilities, error circumstances that are particular to the program, and usability aspects in addition to evaluating other critical features.

3. UI Testing

UI testing verifies that the app’s UI and API functions. This kind of testing makes certain the API is effectively processing the UI’s inputs and that the UI is appropriately reflecting the API’s outputs.

  • When UI testing is essential

The user interface of the software is where the user completes all of their actions. User experience standards are always improving as more and more websites and apps compete with one another in their respective fields. To prove every feature is working as designed, UI testing is required to achieve these criteria.

There are two primary aims of UI testing. First, see how the program responds to input device movements made by the user. The second step is to confirm that all visual components are visible and functional. Organizations can only guarantee that apps fulfill their functional needs and are effectively adopted by end users by taking this action. Because of this, UI testing is important before the software goes into the production process.

4. Load Testing

To make sure the API can manage lots of simultaneous users and demands, this kind of testing replicates scenarios with significant traffic & use. To simulate traffic, load testing is quite similar to performance testing services. However, rather than simulating traffic spikes, the goal is to simulate a consistent stream of traffic that flows at a typical pace.

  • When Load testing is essential

In addition to being a proactive step that you should do regularly, load testing is especially crucial before and after high-traffic occurrences or after you make changes to your application’s design, system connections, or code algorithms. When a website is still under development is the ideal moment to load test it. This will enable you to find possible problems before the general release of the application.

5. Security Testing

The goal of security testing services is to find API flaws that might allow for illegal accessibility, data leaks, and additional security events. This involves checking the API for typical security flaws such as incorrect authorization and exposing personal information. Protecting user data from threats requires making sure the API is safe. Methods like vulnerability & penetration testing are often used. They guarantee that the API complies with organizational requirements and assist in identifying weak points in security implementations.

  • When Security testing is essential

Security testing is required for an application to verify that personal data remains confidential. Security testing is crucial to software testing since, in the end, it helps us preserve the data that we need.

6. Integration Testing

What are the types of API testing? This testing type evaluates how effectively the API works with other parts and services that it uses. The goal of this kind of analysis is to confirm that the API functions flawlessly within the wider ecosystem. It ensures that data moves across systems appropriately and there won’t be problems with integration. Integrating with databases & other best API integration platform services, along with testing the API in a genuine or virtual environment, are common steps in the procedure. Robust integration testing helps to stop unforeseen production behaviors brought on by external dependencies.

  • When Integration testing is essential

The optimal time to utilize integration testing is when a system has all of its components integrated. End-to-end scenarios that simulate how a real user could engage with it should be the main focus. End-to-end system testing, often known as integration testing, is the process of confirming from the user’s point of view that every component of an integrated system functions as intended. This is frequently thought of as a task to be completed right before release.

7. Regression Testing

Regression tests are carried out following API modifications, including updates or bug patches, to ensure that the latest code hasn’t negatively impacted already-existing functions. Identifying any problems generated by the most recent modifications necessitates rerunning earlier tests against the revised API. Regression testing services are a proactive approach to preserving the integrity of the API over time, making sure that improvements or fixes don’t cause new issues. Regression testing is usually managed effectively using automation, particularly for large-scale or regularly updated APIs.

When regression testing is essential-

  • When the new version was introduced

Before a fresh version of the product is launched, regression testing is carried out to ensure that the program operates flawlessly in every situation. For example, before release, we must ensure that the product maintains its functionality in a production setting.

  • When the code is modified, or the problem is fixed

Assume a tester finds that the website’s registration form isn’t working correctly. The tester will confirm that the registration procedure yields the intended result once the developers have fixed the issue. Simultaneously, the tester verifies that the related login features are functioning properly.

  • Whenever there is a change in the surrounding environment

Five common environments are utilized in the SDLC: development, performance, alpha Example, and real-world production instance of beta 5. Before a new instance of the product is launched, regression testing is carried out to ensure that the program operates flawlessly in every situation.

Also Read: Top Effective API Performance Testing Tools In 2024

8. API Hacking

Security testing methods that take advantage of API loopholes are known as API hacking. Attackers can use endpoints of the API to take over the system, block solutions, or obtain data access. Attacks against purposefully weak APIs, which may be obtained from the Internet, can serve as training exercises for ethical hackers. They may then use the company’s APIs to assess their robustness and identify any vulnerabilities.

  • When API Hacking testing is essential-

A key factor in guaranteeing strong online application security is API hacking. It is a two-edged tool that may be used by malicious as well as pro hackers. For a start, API hacking makes it possible to find security flaws in the application’s API layouts, which enables the fixing of these problems before they become exploitable. We may comprehend potential security issues in the API creation and execution by simulating possible attack vectors using API hacking. API security testing boosts the tracking & resolving rate of vulnerabilities and the possible danger they cause to a business.

9. Runtime Error Detection

The goal of runtime error identification is to locate and fix problems that arise when the API is in use. This kind of testing requires maintaining an eye on the API while it’s being used to detect any unusual behaviors or exceptions that could affect security or efficiency. Thorough logging and monitoring techniques are needed. API teams may increase the reliability and consistency of their services by quickly detecting and fixing runtime problems.

  • When run-time error testing is essential

A software assurance technique called runtime error recognition examines a program as it runs and reports any errors found during that process. It may be used in penetration testing, automated/scripted system testing, integration testing, unit testing, and component testing. A hardware or software issue that stops Internet Explorer from functioning properly is called a runtime error. When a website employs HTML code that isn’t compatible with the features of the web browser, runtime issues may result.

10. Unit Testing

Unit tests check that an API’s testable components known as units work as designed when tested separately. These are mostly produced & implemented by the development team, facilitating in finding of problems before the development process. The main focus of unit testing is, making sure that each component completes its assigned function. Unit testing has several benefits, such as quicker development, simpler troubleshooting, and better code quality.

  • When unit testing is essential

Every feature or stage of the development process has to have validation tests conducted when it is finished. Unit tests are a type of validation test that is executed after the creation of each unit of code. Once many components have been finished separately and are prepared for combination, integration tests are conducted.
To guarantee that the tests are effective and successful, use the appropriate frameworks and API testing type for API testing.

These are essential for analyzing factors including cost-effectiveness, scalability, ease of use, and interoperability with existing systems. It’s crucial to assess the kinds of tests that need to be run in addition to the capabilities that are available for ongoing maintenance and growth. You may choose a framework that best meets your needs and enables you to create comprehensive API tests based on the criteria.


Boost Your API Expertise: Explore Testing Types!

To guarantee software development’s security, quality, and dependability, API testing is essential. A sound plan may lower risk and enhance the overall standard of the software application by assisting in the early identification of problems during the development cycle. Developers may verify that APIs are functioning as intended and are error-free by adhering to recommended standards for API testing. By learning the above blog, you may now have a better idea about what are the different types of API testing & their role.

The foundation of software creation that ensures application functioning and seamless interaction is API testing. For programmers and QA specialists, a thorough approach to API testing, encompassing functional, load, and unit testing, is crucial. Applications are becoming more linked and dependent on APIs; thus, it’s imperative to use efficient testing methodologies.

If you want high-performing apps that satisfy developers’ and end users’ requirements, talk with the API testing company. Meet with the professional QA testing team and let them investigate which type of software testing is ideal for your software application.

QA teams utilize the API Testing Strategy as an action plan to test and make sure that the desired outcomes and expectations are met. It entails creating test cases, specifying test criteria for entrance and exit, creating test cases, figuring out the test information, and running the tests. API testing aims to find any bugs or risks in the API before putting it into production.

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About The Author
Digital Marketer at KiwiQA: Software Testing Service Provider Company Worldwide.

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