One of the most pressing issues with application programming interfaces (APIs) is that they are often viewed as an afterthought rather than part of a company’s development process. 

Once built, they can’t just be left to fend for themselves. Rigorous and continuous testing must be done at all stages of API design, development, and production to guarantee functionality, reliability, performance, and security. Better yet, it’s good to have an idea of endpoints and several tests to lay out the perimeters of your API design before you start. 

Whether you’re using a SOAP (Simple Object Access Protocol) or a REST (REpresentational State Transfer) API, there are multiple tests for developers to consider:

• Functional Testing - to verify responsiveness and perimeters 
• User Interface (UI) Testing - to test the backend of your application with another 
• Security Testing - to check for vulnerabilities, including setting up SSL certificates
• Load Testing - to test the robustness of your application
• Runtime and Error Detection - to check for implementation errors and malfunctions 
• Validation Testing - to test your elements (e.g. documentation) against your criteria 
• Fuzz Testing - using unexpected values to test your application’s limits
• Unit Testing - to verify small portions of code separately 
• Integration Testing - to analyze combined portions of code 
• Performance Testing - to check the overall running
• Stress Testing - to test how your system works under an unexpected load
  

Good tests save time. Starting with testing means that these same tests will be on your side when addressing errors that may arise. Testing in line with development is one of our principles for good API governance. So, with functionality in mind, here are our three top tips for developers to enhance API testing.

1. Automate API functional testing

You may choose to manually test and write your own code to set up environments that invoke API with the required set of parameters. However, in the next two years, the number of API testers who automate their tests is expected to grow by 30%. API testing is easy to automate and can save hours of time compared to boring and lengthy manual procedures. 

Automated tests for APIs prevent human error, streamline continuous testing, and catch bugs quickly. By increasing test coverage and frequency, developers are able to spot and predict error codes and malfunctions faster and see less disruption to user experiences. Of course, the crux of DevOps is that you want to automate anything that you have to do more than once, which frees developers and QA to do more. 

A cloud-based, low-code API management platform makes it simpler to write automated tests that update and sync with endpoints not to break any user workflow. The benefit of using a cloud-based platform is that it ensures everyone has the same test version across your organization. A unified platform further chains together complex API workflows to test cases on-demand, or using CI/CD, to increase deployment frequency and avoid disruption caused by manual errors.

2. Continuous testing across multiple environments

Many developer teams test across local dev, staging, and production environments. Therefore, basic API smoke tests should be running for every API, endpoint, and environment, so any big problems with API deployment are immediately detectable. Smoke tests are very different from complex end-to-end tests as – due to their preliminary nature – they involve fast execution. 

With a platform-based approach, developers can create a controlled environment in a sandbox for API mocking and functional testing. An API sandbox, supported by a full range of API documentation, allows testers to mimic the characteristics of the production environment and should be a priority when thinking about improving developer and user experiences. Developers can even consider using their tests as part of their documentation for those looking to adopt the API. 

Continuous tests are crucial for the back end and the front end. Developers must understand the endpoints of their API to create the right tests. For example, if they integrate with a web service, to catch inaccuracies before writing production code. It’s important to also clarify these endpoints and any error codes in your API documentation to make your developer experience more self-service. 

External services can also affect your applications, and, sometimes, you’ll have to update code to bring the APIs up to date with an external service. Continuous testing is the best way to catch this type of error early before it affects runtime performance. An API management platform should enable you to integrate this continuous testing right into your CI/CD pipeline for cross-organizational visibility.

3. Stress test the limits of your API design

Developers or testers must “add stress” to the systems you are building to test the limits of your API and foresee potential problems before they even occur. Adding stress can include checking endpoint security, testing data validation, and error messaging handling.

Known as edge cases, extreme tests can give reasonable confidence that, if APIs are used in an unexpected way, they’ll behave the same everywhere else. For example, test through intentional wrong inputs and invalid parameters, or test out when an API would block a request saying you’re not authorized. All of this can be automated with the right API management platform.

Most importantly, create and follow a plan for test maintenance to keep the tests up to date and functional. Determine how often the tests will run and how they will be deployed. A successful API testing program is continuous, running in production as part of your ongoing delivery pipeline. Remember, even if you don’t make a change to your API, behavior may change on the other side of the connection.

Try low-code API management for continuous testing

Low-code API management platforms are a great solution to transform all aspects of API testing, so APIs work across all platforms and don’t suffer from data corruption.

You are most likely already testing your APIs regularly, but the testing processes can be streamlined further through low-code management platforms. For more information, get in touch today!