API Test Automation: Strategy & Tips

Absolutely all typical QA processes include API test automation. What’s more, this type of automated testing is conducted not only by specialized experts but also by developers while working on the product, meaning at the foundational level.

The popularity of API automation is evident in the market capitalization, which reached $1.07 billion in 2022. According to the forecasts of Data Bridge Market Research analysts, by 2032, the industry’s value will reach $4.73 billion, with a CAGR of 20.4% during this period.

Comparing these figures to the overall QA niche indicators, we can see that the share of API automation testing constitutes about 1/20 of all types of testing. This is not insignificant, considering the specificity of this type of testing.

API test automation is an integral part of QA because, as a rule, all modules and most functions of modern software (especially cloud-based ones) are implemented through APIs. Interactions with the system, database calls, and even external requests are triggered through APIs by various commands.

Sergey Almyashev

COO, ZappleTech Inc.

The experts at ZappleTech have prepared a guide for you on the principles and strategies of API automation. From the material, you will learn:

• The types and levels of API checks.
• Why it is critically important to test this component.
• Which tools are advisable to use.
• What to pay attention to during testing.
• How to document and verify test results.
• Why it’s better to outsource this type of QA.
• How to choose a contractor.

Get comfortable; an interesting long read awaits you. We guarantee you won’t be bored! And we’ll start traditionally with the basics of API automation.

API Testing Paradigm: Understanding API Testing Levels, Identifying Critical APIs for Testing

When we talk about API test automation, we often imagine certain communication gateways that perform various tasks. For example:

• Data exchange with system components.
• Calls and responses between modules.
• Connection protocols, often with financial channels.
• System calls (such as iOS or Android sharing menus).
• External integrations (payment gateways, databases, etc.).

And in fact, this corresponds to reality, but API itself is somewhat broader. It operates within a single program or connects two or more apps.

That’s why API automation integration testing is an essential part of QA because only API test automation verifies whether this component functions correctly. It also ensures secure data exchange and relevant output. For this purpose, tests are divided into several levels.

API testing levels

The hierarchy of API test automation is not much different from other types of automated tests.

It also has a clearly defined structure and includes several basic levels:

• Unit: The lowest level, tested directly by developers after completing a code segment.
• Integration: QA experts check how components interact.
• System: Similar to the previous level, QA engineers do testing in the context of API automation and interaction with the system as a whole.

There are also advanced levels:

• Functional: Checks whether the API complies with specifications and performs programmed functions properly.
• Performance: Examines API behavior using API test automation under various loads.
• Security: Examines the API for vulnerabilities and their potential impact on product security.

But that’s not all, as certain APIs require more attention. Let’s delve into critical APIs.

Critical APIs for testing

In today’s software market, two categories of digital apps prevail, popular enough to claim a significant share of the industry. These are the Fintech and HealthCare fields, where user information is sensitive and critical. However, it’s not just about them, as there is other software whose data can work not only positively.

That’s why, in API test automation, it’s essential to focus on important aspects of the program and APIs, such as:

• Those with direct access to personal or financial information.
• Those interacting with external servers, databases, or third-party software.
• Those involved in control, such as power management systems for devices or smart homes in general.

Commerce, banking, healthcare, logistics programs, and control systems: everything mentioned above can have vulnerabilities that threaten personal information or even entire residential complexes, and thus, comprehensive API test automation should be carried out during software development.

And it’s equally important to do it efficiently, using specialized tools.

Analysis of Specialized API Testing Tools, Custom Tooling Considerations for Unique Scenarios

Every job requires its own set of tools, especially API test automation, where the efficiency of processes determines functionality and data security.

Even complex systems like Appium or Selenium can be used for API automation. However, their scope is somewhat broader and does not allow for detailed scanning of APIs for issues, although they do provide some capability in this regard.

Today, we will focus on specialized software for API test automation used by ZappleTech experts. It has proven its effectiveness in practice, so these testing tools can be confidently recommended to anyone looking to conduct API automation.

Postman

In a broad sense, this tool is not solely intended for API test automation. It is primarily designed for creating, modernizing manual testing, and implementing APIs in software. However, QA experts successfully use it for API automation.

The key advantage lies in its niche IT solution. It allows you to implement APIs and immediately initiate API test automation. This is quite convenient and efficient, especially in large-scale projects.

JMeter

Again, this tool is not exclusively designed for API test automation but serves a broader purpose. Its primary application area is performance testing of software. However, API automation is effective within this load testing framework, even as a secondary function.

The advantage of this tool lies in its versatility and user-friendliness. It works with the same data formats used in traditional API automation, and its protocol scanning quality is high. Therefore, it is a justified choice and quite popular among QA professionals.

SoapUI

It is a unique testing tool used for API test automation that allows checking interfaces and creating or modernizing them. Using this QA software, you can effectively test APIs and integrate the results directly into development environments through CI/CD pipelines.

Thus, this framework is perhaps the optimal solution for API automation, especially if you create and modify proper test cases during the QA process.

Crafting Scalable and Robust Test Cases

Like in most QA tasks, API test automation is effective only when you plan your work in advance.

This means that the cases for API automation should be simple but only up to a certain point. Initial scenarios are developed to test a single fragment or action. Subsequently, these algorithms gradually merge into complex tests, which become the basis of your API automation strategy.

Incorporating data-driven approaches for varied scenarios

First and foremost, you need to determine the range and type of data you will use for API test automation. Interfaces typically involve information exchange – in essence, there is a call and its result, meaning a response.

You must inject the appropriate data to verify whether these interfaces are functioning correctly during API automation. These can be numbers, phrases, or simply reproductions of specific actions.

Mykhailo Poliarush

CEO, ZappleTech Inc.

Furthermore, this data should be valid, and any irrelevant values should either return an error, be interpreted, or simply be discarded. This is an additional goal of API test automation.

The best part is that the industry already has a clearly defined list of data formats that QA professionals use during API automation testing.

Data Formats: JSON, XML, and Beyond

Data exchange standards in software include JSON and XML formats. These are markup languages that specify the range, type, and specifics of information. In API test automation, they are used for sending data to the interface and receiving responses from the system, documenting processes, and more.

In addition to the mentioned formats, other formats, such as HTML, can be used in API automation, but it is not an effective method for several reasons. Generally, project specifications usually define the data exchange format, which becomes the standard for the team. Typically, this standard includes formats like JSON, XML, and others.

Implementing data integrity checks and payload verification

It’s not without reason that we consider these formats in the context of API test automation. These formats are easier and quicker to verify, and it’s simpler to check the integrity of the data they contain.

Data validation is one of the most important components in the processes of API automation. This is because even a seemingly minor deviation can lead to catastrophic consequences for the project.

Mikhail Bodnarchuk

CDO, ZappleTech Inc.

For example, an API that was tested may later become non-functional because its testing was done using data specifications that didn’t match.

To prevent such cases, it’s essential to verify the data and configure the working environment correctly.

Managing Testing Environments With Dynamic APIs

An integral part of API test automation is working with dynamic interfaces. These are interfaces that, depending on the request, can interact with different subsystems of a digital product or test environment.

For such IT solutions, special methods of API automation and test environments that simulate real user interface behavior are applied. “Stubs” are used for missing modules, and the functionality is verified through investigative means.

This ensures that the component will work as intended. However, this is not a one-time operation, so ensuring that your team does not get confused in iterations is essential.

Version control considerations for API changes

Version control is a common practice in API test automation that ensures the proper state of each iteration of the API in the context of QA.

This means that you need to document all API automation processes, specifying the version of the application programming interface for which the verification was conducted. Then, an archive of reports is used to work on errors, check changes in the API, or simply maintain the team’s focus.

In addition to the above, you also need to introduce metrics by which you can evaluate not only the effectiveness of security testing and the verification but also the overall performance of the API.

Setting Performance Benchmarks for API Endpoints, Stress Testing for Resilience and Scalability

Consider the project specifications and requirements to assign certain digital performance indicators for API test automation. You will need these indicators to determine whether the performance and functionality of the API test scripts align with specific standards.

This will help you measure the KPIs of API automation and provide digital results that you can document as qualitative metrics.

Additionally, thanks to these metrics, you can monitor the performance of both API automation and the overall API functionality in real-time.

Real-Time Monitoring of API Health and Performance, Implementing Alerting Mechanisms for Critical Failures

And again, about monitoring API test automation. You need to configure the system so that the metrics of API tests and automation are sent directly to a dashboard or even implemented into CI/CD tools.

As a result, you will obtain comprehensible metrics for API test automation that you can use in future QA processes. For example, for comparing the performance of iterations and identifying factors that impede the functioning of interfaces.

Additionally, you can use the metrics of API automation to create qualitative and understandable documentation, reports, and more.

Building Clear and Concise API Testing Documentation, Leveraging Detailed Reports for Actionable Insights

Like in API test automation, proper documentation is a fundamental element at the core of QA. Reporting, the test coverage, cases, notes, and observations must be thoroughly documented.

Primarily, this is done in order to:

• Maintain focus during API automation.
• Have the ability to review past operations.
• Provide comprehensive reports to developers, PMs, and stakeholders.
• Understand the state of the product, its overall quality, and issues.
• Avoid duplicating operations.

Therefore, this documentation will help your team work more effectively, track performance metrics, and stay on course during the API test automation project.

But are you confident that you can handle this task on your own? Perhaps it’s better to delegate some of the QA routine to specialized professionals? We can help you choose the right API automation service provider.

Key Criteria for Selecting Specialized API Testing Contractors, Assessing Contractor Experience and Technical Proficiency

You need a team for API test automation. What do you need to do to select an expert professional?

• Find several companies offering their API automation services.
• Evaluate the experience and expertise of each of them using: test tasks, portfolio cases, reviews on platforms like G2, TrustPilot, DesignRush
• Ensure that the team can work with your type and niche of IT solutions.
• Talk to a manager to determine the contractor’s pricing.
• Create a contract outlining key terms, NDA, deadlines, scope of work, areas of responsibility, and more.

All of the above almost guarantees you will receive quality API test automation services. However, you should consider the specifics of outsourcing, which can have both positive and negative aspects.

Leveraging External Expertise for Specialized Testing Needs, Overcoming Outsourcing Challenges for Seamless Integration

Usually, the concept of outsourcing is associated with several risks, including:

• Difficulty in managing the contractor’s team.
• Poor communication and reporting.
• Relatively mediocre quality of work.

However, this is typical in cases where you choose an inexperienced contractor. With professionals like ZappleTech, the situation is the opposite. That is, you get:

• A self-organized service provider.
• Top-quality API test automation.
• Detailed reporting.
• Integration with CI/CD tools.
• Responsibility.

But, these are not all the advantages of collaborating with industry leaders like the ZappleTech team.

ZappleTech Will Provide the Best Services for API Test Automation

If you need expert assistance with API test automation, you can delegate your project to the professionals at ZappleTech. What’s more, the company can fully address all your QA needs, ensuring the highest quality for your digital product.

With over 10 years of experience across various industries and types of IT solutions, hundreds of satisfied clients and completed projects, a 99% positive rating on industry-specific platforms, and dozens of visualized case studies – it’s all about our team.

Want to make sure that ZappleTech is the perfect QA automation service provider? Contact our brand manager for a free consultation or demonstration.

We guarantee that by entrusting your project to us, you will permanently rid your digital product of bugs.