APIs are rising both in quantity and business value. But with that growth comes an increasing number of vulnerabilities, which could affect cloud service dependencies and internal APIs. Functionality and uptime could also suffer as cloud services evolve their APIs with new versions. Thus, API endpoint testing is critical to ensure a reliable back end. With growing interest across the organization to stabilize these integrations, how do we test APIs in a reproducible way that non-developers can grasp?

Low-code platforms — tools that enable workflows with visual programming models — are opening doors for citizen developers to construct applications in a visual mode. Similarly, the low-code concept could aid API testing by providing an easier method to create API tests to verify functionality and uptime. This could arm quality assurance, DevOps and site reliability professionals with an easier means to test high-value integrations and their UI representations.

Amid a growing headless movement, APIs are now powering many end-user experiences. However, during a developer drought, it may be challenging to find talent with integration know-how.

I recently met with Dan Belcher from Mabl to discuss combining low-code and API testing. Here, we’ll uncover why it’s difficult for non-engineers to conduct API testing and consider what API testing must address to ensure today’s software meets tomorrow’s digital innovation demands.

A Low-Code Approach to API Testing

The software landscape has evolved rapidly in recent years. “Many forces have combined to create an incredible amount of change,” said Belcher, citing DevOps, CI/CD, the API economy and agile enterprises as examples. In this era, applications are becoming more dynamic, disrupting the way teams conduct end-to-end quality testing.

API-based cloud services are part of this new frontier, becoming popular building blocks within modern applications. Yet, integrations require upkeep as cloud services evolve and version. Without continuous testing of API-based cloud services, organizations could easily suffer from breaking change and poor usability.

Unfortunately, as it stands, typical QA teams aren’t well-equipped to handle ongoing regression testing for APIs. Instead, “developers, historically, have been the only ones that understood API testing,” explained Belcher. For years, API testing has been relegated to the realm of developers, who use tools like Postman to perform unit-level testing. But why is API testing so difficult for others?

What Makes API Testing Difficult?

Well, to start, non-engineers are typically more accustomed to UI-based testing. These environments use a structure designed for anyone to consume, making it easy to locate fields and confirm values, Belcher explained. When it comes to API testing, you often must handle massive chunks of JSON responses to match fields and surface issues. Testing API responses typically requires writing code, parsing JSON and writing it to variables, Belcher explained, which may be difficult for non-developers to implement.

Or, difficulties could arise when testing asynchronous endpoints, Belcher added. Asynchronous APIs often involve background server processes that take a while to respond. This comes at a moment when event-driven architecture (EDA) is a growing trend. Take AsyncAPI, a standard API specification for EDA APIs, which recently joined the Linux Foundation. A recent report found AsyncAPI production usage tripled from 5% in 2019 to 19% in 2020. According to Belcher, testing such asynchronous services requires an infrastructure for continuous testing to anticipate these emerging scenarios.

Four Crucial Areas For API Testing

So what should API tests be focusing on? Belcher highlighted four areas that warrant close examination throughout the API testing process:

Functionality: This is the core functionality. Does the API do what it promises? Does it return the correct data?
Uptime: What is the API’s availability? Are all endpoints available in production?
Speed: This ensures cloud dependencies meet SLAs. What is the latency? Is there drift in API performance over time? Though API monitors like Api.expert help aggregate industry performances, they might not always reflect your specific customer-level realities. Belcher recommends not placing faith in supposed performance and instead, clocking your own.
End-to-End: Belcher stresses the role APIs now play across customer-facing presences. An end-to-end workflow should involve API endpoints, how they interact with one another, and the resulting visual representations. “Just like we have end-to-end testing for UIs, we should have end-to-end testing for APIs,” he said.

API testing isn’t always combined with other parts of the user experience, but Belcher believes, going forward, end-to-end testing will be critical to ensure all workflows function in concert. For example, if a user profile is created within a browser, teams should verify the user profile has been created at an API level, as well.

Low-Code API Testing and Shift Left

APIs are beneficial to avoid reinventing the wheel. However, 100% operational uptime is impossible. Applications will inevitably encounter API problems, including outages, technical failures and functional misrepresentation. Developers also often come to rely upon production behaviors that may not be officially documented, an effect known as Hyrum’s Law. This can cause unstable integrations as APIs version over time.

Thus, for these reasons and more, it’s a good practice to adopt continuous API testing. With the surging interest in site reliability engineering, spotting API errors early on will become an important aspect in reducing mean time to recovery (MTTR). Testing third-party APIs could also expose production latencies to inform cloud investments.

“As the pace of change is going up, how do we deliver great quality to our customers?” Belcher asked. API testing is one answer to address this rapid change, and is growing in importance for the software delivery life cycle. It especially rings true for headless frontend experiences, where the API-driven backend isn’t transparent to QA testers.

Low-code capabilities for API testing could help tear down silos inherent in the development process, enabling more people to participate in testing integrations. Belcher also stresses the importance of improving the usability of API testing for developers and non-developers alike. “We need to integrate with tools developers are already using for verification,” he added.