When an API fails and disrupts the performance or user experience on your site this failure reflects on your company. End users and customers likely won’t recognize that a third-party could be at fault. And depending on how critical that API is to a transaction process, this failure could impact your bottom line right away.For example, if a key component of the checkout process on your website is a location-based search and you rely on a third-party API to provide the search by location, when that API doesn’t work correctly then your potential customers cannot checkout successfully.

Or, imagine that you developed an application that requires authentication from a social media platform. If the API for that social media platform goes down, your users might not be able to log into your system.

As a developer or a site owner, you may decide that the benefit of relying on the third-party service outweighs the risk of these types of failures. In order to accurately assess the risk and have visibility into the impact of these services over time, it’s crucial that you monitor the part of your site’s user flow that relies on an API.

If you have an open API that you’ve made available to partners or developers, then you have a responsibility to ensure that the API is available and working as expected.

Or, let’s say that you’ve developed a new internal API that passes order data from a mobile device to a system in your product warehouse. Maybe it’s critical that the data passes to the warehouse within 2 minutes time, or the entire production schedule will be off. When you developed the API and tested it in staging it always passed data successfully within one minute, but when you launch the API and start processing real requests you notice that the real response time is creeping up closer and closer to that 2-minute threshold. Without active monitoring on the API in production, your team might assume that the developed API is fast enough based on pre-production tests.Web-APIs-v5_0


Note: If you host an API that other people rely on, be sure to actively monitor that API
in both pre-production and production environments.

Whether it’s to keep tabs on your own APIs or see the impact of external services that you rely on, it’s important to monitor APIs for availability, functionality, speed, and performance. If you know you have an API that’s been unreliable in the past and you’re not actively monitoring that API, start the conversation with your team and develop a plan to begin monitoring that API today.


What to Monitor

So now that you understand why it’s crucial to monitor API performance, you also know that you should consider both:

  • APIs that your website or native application relies on for critical data or processes, and
  • APIs that you manage that customers, end users, or developers rely on for data or processes

When monitoring both of these types of APIs, it’s important to test:

  • Availability – Is this API endpoint up? Is it returning an error?
  • Response Time – How quickly is the API returning responses? Is the response time degrading over time? Is the response time worse in production than in pre-production?
  • Data Validation – Is the API returning the correct data in the right format?
  • Multi-step Processes – Can I successfully save and re-use a variable from this API? Does authentication work as expected? Can I complete a transaction with data from this API?

These are just the basic concepts that your team should be looking for when it comes to monitoring API performance. In the next section we’ll cover how to technically implement monitoring for APIs and what types of features are important to build out robust, flexible performance tests.