The Essential Guide to API Testing for EDI Integration

6min read



Application programming interfaces (APIs) are used to optimize organizations across every industry. They ensure performance and secure integration between software systems, so thorough API testing is vital.

APIs benefit developers who need their programs to reliably communicate, but that doesn’t mean their integration is always seamless. API testing verifies that connections are reliable, secure, and efficient. Before you implement an EDI system, take time to learn more about API testing and why it's so important.

API testing types

Developers use several types of API testing to ensure an interface is working correctly. These are the most common testing methods used in the EDI industry:

UI testing

UI (user interface) testing is one of the few types of API testing that doesn't focus on the back end. Instead, UI testing ensures an application’s interactive and visual elements work as intended and meet the user’s needs. A good UI is simple, uses colors and textures strategically, and clearly communicates any errors or changes in system status.

Functional testing

Functional testing is just what it sounds like. It tests specific functions to make sure they work properly. This type of testing goes a step further than UI testing. Everything may work well during a basic UI test and then fail when you use more rigorous methods. Functional testing allows you to test a few edge cases to ensure that your interface works under various conditions.

Security testing

Before you connect one interface to another, you need to make sure the API is safe from external threats. This type of testing focuses on user access controls, encryption, and other security features. For example, security testing verifies that each user has the appropriate permissions.

Fuzz testing

Fuzz testing is another way to ensure an application is as secure as possible. During this type of test, testers feed random data — known as fuzz — into the system and observe the outcome. If introducing fuzz causes the system to crash or produce an error, developers can address the problem before the app goes live.

Validation testing

Validation testing is one of the final steps to determine whether an interface is ready to launch. It tests whether the interface meets the user's needs, performs as intended, and conforms to applicable security standards.

API testing versus unit testing

A search for "What is API testing?" often provides results about unit testing. In reality, API testing and unit testing are related but distinct processes. API testing validates an API in isolation and when it's connected to other applications, whereas unit testing checks individual components as soon as they're ready. Here are some of the most significant differences between API and unit testing:

  • Timing: You don't perform API testing until the build is complete. Unit testing is performed as each module becomes available.
  • Personnel involved: Developers perform unit testing to determine whether they need to tweak a module before moving on to the next one. Dedicated testers perform API testing to make sure the whole build works correctly.
  • Scope: Because unit testing focuses on single modules, it's somewhat limited in scope, with developers focusing on just one unit at a time. The scope of API testing is much broader, focusing on multiple modules and how they work together.
  • Source code: Developers have access to each module's source code, so they can make changes as needed. Testers have no access to the source code. They can alert developers to a potential problem, but they can't make any changes to the API.
  • Level of testing: Unit testing focuses on basic functions, while API testing focuses on advanced functionality.
  • Sequence: Unit testing only tests one module at a time, so it does not help determine whether the sequence of functions is correct. API testing focuses on end-to-end functionality, which verifies that data flows well and everything happens in the correct order.
5 methods to test an API

API testing is highly flexible, so you don't have to follow the same steps or use the same methods every time you conduct a test. You can use any of these methods to ensure an API works as intended.

  • Security testing: If you're concerned about data breaches and other security threats, use security testing to verify encryption and check other security features.
  • Documentation: With this method, the testing team confirms the documentation accompanying the API is adequate. Documentation should provide enough information to help users interact with the API correctly.
  • Discovery testing: This method executes a set of calls to establish whether the API responds appropriately. For example, you can test if a resource is deleted or created.
  • Automated testing: With automated testing, you employ an API testing tool, such as a script, to execute the API.
  • Usability testing: This involves observing users as they interact with the API and prompting them for feedback. This verifies you have a user-friendly API that functions as expected.
Best practices for API testing

When you're ready to get started with API testing, follow these best practices to produce the best possible results:

  • Create as many API test cases as possible to ensure you can identify issues before they disrupt business operations.
  • Group your test cases together by category.
  • Make it easy for testers to work with your API.
  • Ensure test cases are self-contained. Isolate the test case and the data you want to test to reduce variables.
  • Use caution when working with one-time call functions like CloseWindow, Delete, and other one-time call functions.
  • Include API declarations at the top of each test.
  • Integrate API testing into your product development pipeline.
  • Test at your system's boundaries. You won’t find as many potential problems if you only test common use cases.
Benefits of API testing

API testing has many benefits — most evident is the opportunity to refine your API before you launch it or integrate it with another application. API testing is also language-independent, meaning you can verify functionality regardless of programming language. It takes much less time than UI testing, and you can create a wide variety of test scenarios, helping you identify minor errors before they become major problems.

Challenges of API testing

Although API testing has many benefits, it also comes with technical challenges. First, there's no graphical user interface available, so it's harder to input information. API testers are generally developers with coding knowledge, not customers that can give user feedback. Even with coding knowledge, testers may need help validating and verifying an API’s output. Finally, you need to test its exception handling — how an API addresses errors during execution — which makes the process a little more time-consuming.

Orderful enhances your partner relationships

Now that you understand the importance of API testing, you're armed with the information you need to transition to an EDI platform. Orderful offers a cloud-based EDI solution for all your communication and payment needs, eliminating the need to invest in your own hardware and software. The platform uses modern APIs, making it easier to connect business systems and trading partners.

Ready to benefit from EDI without the hassle of creating an in-house system? Speak with an expert at Orderful to learn more about your options.


Go live with new trading partners in days, not months. Orderful’s modern EDI platform standardizes integrations and streamlines testing, getting your business connected with partners 10x faster than other solutions.

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