What is API Monitoring?

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What is API monitoring?

The increasing complexity of modern websites and web applications means that a dependency on Application Programming Interfaces—or APIs—is unavoidable. APIs are used throughout software to define interactions between different software applications. They are also indispensable to businesses as they enable them to develop applications that can scale and provide a wealth of services without the need to build every software or server component from scratch. APIs have been instrumental to the growth of applications and their subsequent reception by end-users. In a sense, they are the building blocks of any modern application.

There are several types of APIs, including REST, GraphQL, SOAP, custom homegrown approaches and many others. Every API approach has pros and cons, and the implementation details often depend on the teams building the API and the application consuming it. An API usually consists of multiple API endpoints that reflect actions or resources in the form of a URL that applications can interact with.

And while using APIs imparts a great deal of flexibility in how your applications are built and used, issues with APIs can cause a domino effect that adversely impacts other components that rely on them.

Given the importance of APIs, we need to approach the testing and monitoring of API endpoints and URLs both individually and as part of a business flow. Even when looking at non-public APIs, verifying that they are both correct and performant is essential as they are the foundations on which any business-critical service is running. Given the importance of APIs in the tech stack of every modern business, you can’t afford to not monitor your APIs.

In this article, we’ll explain what API monitoring is, why it is important, and how to get started with an effective API monitoring regimen.

API monitoring explained

API monitoring is the fairly straightforward practice of evaluating how an API is performing via a number of different metrics, including verifying availability, verifying correctness (i.e., is the data that is being sent correct?), and measuring performance and asserting that against a performance threshold. The goal is to determine whether the APIs are functioning as they should and whether they are available and functioning at an optimal level for the other applications and services that rely on them.

Tracking performance data of APIs, such as response times and variations in performance in the context of different environments, enables you to identify issues with them before customers and other stakeholders do, helping you avoid extended periods of downtime or degraded performance.

Why is API monitoring important?

When a web application or website delivers less than optimal performance—or fails entirely—the impact on your business or on customer experience can be significant. API monitoring solutions can be used to check your mobile, web app, or other APIs for performance, correctness, and availability.

  • Performance Monitoring: Monitoring an API endpoint for response time to requests could involve measuring TCP, DNS, and first byte times.
  • Correctness Monitoring: Checking that an API is returning the correct data payload, authentication, return codes, and headers and validating that any given API is functioning properly.
  • Availability Monitoring: Whether your API is available from a single location or via multiple points across the globe, availability is a vital monitoring metric. If an API is accessible on a global basis, monitoring that API from various locations across the globe can give you insight into any region-specific issues.

A good monitoring solution can provide information on all of the aspects outlined above. Once equipped with this knowledge, teams can take the appropriate steps to both fix any damage done as well as improve suboptimal APIs for long-term stability.

More importantly, having an efficient alerting regimen working in concert with your monitoring solution can ensure that the right people are notified of problems as soon as they emerge. Precise and accurate reporting then provides additional insights necessary for a successful investigation into the problem. All of this translates into faster time to recovery, fewer problems being encountered by the end-user, and helps mitigate revenue loss.

Do you need to monitor APIs constantly?

With applications relying heavily on APIs for their functioning, monitoring APIs on a regular, consistent basis becomes a necessary practice in any software development and maintenance project. Companies that are committed to ensuring that end-users have a positive and smooth experience with their product often take advantage of API monitoring tools and services to notify them of any issues before customers encounter them.

Around-the-clock, 24/7 API monitoring is essential to catch any issues with APIs that could negatively impact the health of the larger application. Without API monitoring in place, businesses risk the development of gaps in their knowledge of the application’s status, which can have severe consequences for the stability of the application, and the end-users’ experience of it.

Another compelling reason for 24/7 monitoring is that there are multiple points of potential failure in API operations. An update to the API itself might introduce a bug which leads to downtime or performance degradation, but the same might happen due to infrastructure reasons (e.g., maybe a server or a hosted cloud instance is overloaded). API monitoring should ideally be incorporated into a team’s larger testing and monitoring efforts so that they can have a comprehensive view and understanding of the application and its various components at any given point in time.

How can you monitor your APIs?

Now that we have established what API monitoring is and why businesses should adopt it as part of their development process, here are some tips to get started.

The first step is to identify which APIs are currently being employed by your system, including both internal-facing as well as external third-party ones. Understanding the exact role they play in the development of your application is crucial to knowing which metrics need to be monitored and tested. Metrics such as API response time, availability, and data correctness are a few that you will be interested in keeping an eye on.

Requests are sent to the API, whose responses are evaluated in terms of speed, availability, and correctness. In case the response received does not meet the standards laid out for it, the API check registers an error. It is common for monitors to send a second request to that API in the event of a failure. If the API is unreachable or its response is once again inadequate, the user or API provider is informed of the situation.

The next step is to choose an API monitoring tool that will best support your needs. A good monitoring tool will run checks across all your APIs frequently and be able to check for various metrics across criteria such as performance and correctness. With Checkly you can establish a high frequency of checks, which allows you to observe the status of the target system with greater granularity. For example, a critical API endpoint could be monitored every second to ensure that any issues are caught immediately, rather than waiting on a slower monitoring frequency.

Checkly’s API monitoring tool is an optimal solution for companies that are keen to develop and integrate an API monitoring flow into their existing development and maintenance processes.

Checkly enables you to streamline the API monitoring process. You can start by creating or importing HTTP requests for the endpoints you want to monitor, then specify assertions against the response (and response time). There are ample opportunities to customize setup and teardown using scripts that get OAuth tokens or help clean test data. Checkly has data centers in twenty locations worldwide, from which it can run API checks up to every ten seconds. This is crucial to get a comprehensive and accurate picture of the health of your APIs. Finally, depending on your workflow, Checkly also integrates with services such as Slack, email, and Pagerduty to notify you of any incidents.

API Monitoring as Code

You can also use Checkly with Infrastructure-as-Code tools like Terraform and Pulumi to extend the benefits of IaC to API monitoring, having your monitoring defined right next to your existing code and fitting your existing workflows..

Try out Checkly for free and start building your own API monitoring regimen today.

Portions of the post were contributed by Akshat Biyani (@BiyaniAkshat). Special thanks to Giovanni Rago (@rag0g) and Stefan Judis (@stefanjudis) for technical editing. Follow the author on Twitter at @jeffjames3.

Additional API Monitoring Resources

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