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Best API Testing 101: Practices You Should Follow

The use of application programming interfaces (APIs) has increased dramatically over the past several years due to the increased interconnectivity of systems and devices along with the decentralized nature of today's information infrastructure.

Unlike the monolithic architectures of the past, most computer systems today are made up of smaller modular parts. These modules share data and interact with each other via different APIs.

Nearly 90% of developers work with APIs on a daily basis, which is a strong proof of how crucial APIs are to building up today’s applications. Clearly, making sure that APIs are always working as intended should be the primary motto of each API-driven team.

The goal of API testing is to find any problems early on in the development process. This makes sure that the application works well with all of its parts and meets the quality and security standards that were set.

Testing APIs thoroughly and repeatedly at every stage of development ensures that they work, are reliable, are safe, and do what is expected of them. Without testing, they may fail, jeopardizing the software and services you provide.

Benefits of API Testing

Because APIs carry more than 80% of an application's functional and business logic and are constantly changing, it is critical to protect them from failure. API testing consists of submitting requests to an API to determine whether it responds and acts as intended. This software analysis evaluates the API's functionality, performance, dependability, and security, making it a vital component of API development.

  • API testing makes sure that the APIs built for an app meet the expected requirements for performance, security, and functionality.

  • It helps to identify issues early in the development cycle, reducing the cost of fixing them later.

  • Additionally, API testing verifies the communication between the various software components, ensuring the seamless integration of the application.

Overall, API testing plays a critical role in delivering a high-quality, reliable, and secure application.

Types of API Testing

These tests are performed either directly on the API or as part of integration testing.

  • Unit Testing:

This type of testing focuses on individual units or components of the API to ensure they work as intended. The aim is to catch bugs early in the development process and improve the overall quality of the code.

  • Functional Testing:

Focused on the functional requirements of the API, it ensures that it meets the needs of the business and behaves as expected. It involves testing the API end-to-end, from input to output, to validate that it returns the expected results for a given set of inputs.

  • Integration Testing:

It is performed to understand how the API integrates with other software components and systems and to ensure that the API works seamlessly with its dependent components, such as databases, external APIs, or front-end applications. Tools like Jenkins for continuous integration and HyperTest for continuous testing can be used to do integration testing.

  • Performance Testing:

This type of testing focuses on the performance of the API under various load conditions, such as high traffic or multiple concurrent users. The goal is to find bottlenecks, test scalability, and figure out how well the API can handle heavy loads.

  • Security Testing:

It focuses on the security features of the API to identify vulnerabilities and ensure the confidentiality, integrity, and availability of sensitive data. It is performed to protect against malicious attacks such as SQL injection, cross-site scripting, and unauthorized access.

  • Load Testing:

To check on the ability of the API to handle heavy loads and high traffic, load testing is performed. Also to evaluate the API's performance under conditions of high usage and determine its capacity for handling large numbers of requests.

Manual Vs Automated API Testing

Both manual and automated API testing have their pros and cons, and the choice between them usually depends on what the project needs.

Manual API testing involves sending requests to the API and looking at the responses to make sure they are correct and meet the desired quality and security standards. This type of testing is often used for exploratory testing and for testing edge cases that may not be covered by automated tests.

Automated API testing involves writing code to programmatically send requests to the API and validate its responses. This type of testing is well-suited for repetitive tasks, such as regression testing, and for testing the API's performance and security at scale.

The State of Test Automation Survey 2022 says that more than 50% of organizations have already started using test automation.

The initial set-up cost and time consumption can be higher with automated testing, but it can prove faster, more consistent, and more reliable in the long run.

Although more than 26% of companies struggle to find the ideal automation tool for themselves.

If the API is still in the development phase and is undergoing frequent changes, manual testing may be more appropriate. On the other hand, if the API is already in production and needs to be tested at scale, automated testing may be more suitable.

Best Approaches for API Testing

There are many best practices that can help improve the quality of API testing, including:

  • Plan your tests: Before starting any testing, it is important to plan out what you want to test and what the expected outcomes are. This includes deciding on the types of tests to perform (such as functional, performance, security, etc.), the data that will be used in the tests, and the tools that will be used to perform the tests.

According to a survey by Tricentis, 70% of organizations that have a well-defined testing strategy in place report higher efficiency and faster delivery times.
  • Use automation: Automating your API tests can save you time and increase the accuracy of your testing. A survey by Forrester Research found that organizations that use test automation see a 25% reduction in the number of bugs and a 60% improvement in test coverage. There are many tools available for automating API tests, such as HyperTest, Postman, SoapUI, and Rest-Assured.

  • Test Early, Test Often: It is important to start testing APIs as early as possible in the development process to catch any problems early. It is also essential to test APIs frequently, as changes to the code can cause unexpected issues.

  • Test for error handling: It is important to test how the API handles errors, such as invalid input or unexpected behavior. This will help ensure that the API returns appropriate error messages and does not crash or cause issues for the consumer of the API.

A study by the University of Cambridge found that 45% of security breaches are due to errors in software design, making proper error handling a crucial aspect of API security.
  • Test for security: APIs can be vulnerable to security threats, such as hacking or data breaches. A report by Gartner found that by 2022, APIs will become the most frequent attack vector for data breaches in web-enabled applications. It is important to test for security vulnerabilities, such as SQL injection or cross-site scripting (XSS), and implement appropriate security measures.

  • Document your tests: Documenting your tests, including the expected results and actual results, can help you keep track of your testing progress and make it easier to identify and fix any issues that arise.

Organizations that have a well-documented testing process are 2.5 times more likely to deliver higher quality software.

Why HyperTest for API Testing?

HyperTest is a game-changing API test automation platform that requires no coding and simplifies the testing process for teams. It is a powerful tool for testing APIs and microservices, and ensures the quality and reliability of the applications.

  • With HyperTest, there is no need to make changes to code or configuration in order to test your application. Instead, HyperTest monitors all traffic to and from the application, automatically building integration tests from network traffic and identifying any API failures or incidents, eliminating the need for manual test creation and maintenance.

  • This allows teams to catch issues early on in the development process, using a shift-left approach that helps to prevent problems from arising later on. This innovative tool simplifies the current method used by QA and engineering teams to safeguard their APIs and microservices against failures.

Head over to this page to learn more on how HyperTest can help you in building up your own API testing suite that is robust and is able to catch all kind of critical failures before releasing it to the production.


What is API Testing?

API testing is a type of software testing that focuses on assessing the functionality, reliability, and security of application programming interfaces (APIs). It involves sending requests to an API and analyzing the responses to ensure they meet expected standards. API testing helps identify issues such as incorrect data exchange, performance bottlenecks, and security vulnerabilities, ensuring that APIs function correctly and interact seamlessly with other software components.

Which is the best tool for API testing?

Is API testing in demand?

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