API monitoring is the practice of evaluating how an API (Application Programming Interface) is performing over time via several different metrics, including verifying availability, verifying correctness, and measuring performance. 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 other applications and services that rely on them. Tracking performance data of APIs enables identifying issues with them before customers and other stakeholders do, helping avoid extended periods of downtime or degraded performance. API monitoring tools can be used to check web application or website performance, as well as mobile, web app, or other APIs for performance, correctness, and availability. A good monitoring solution provides information on aspects such as response time, error rate, throughput, latency, and availability. Having an efficient alerting regimen working in concert with the monitoring solution ensures that the right people are notified of problems as soon as they emerge, providing faster time to recovery, fewer problems encountered by end-users, and helping mitigate revenue loss. API monitoring offers several benefits including improved insights and performance, enhanced API performance, improved API metrics, and API responses accuracy. Each team will have its own primary use case for API monitoring, with common use cases being endpoint uptime monitoring, performance benchmarking, global availability checks, versioning and deployment validation, and SLA compliance monitoring. Around-the-clock 24/7 API monitoring is essential to catch any issues with APIs that could negatively impact the health of applications. To get started with API monitoring, identify which APIs are currently employed by your system, choose an API monitoring tool such as Checkly, set up monitoring frequency, define alert channels, review and save settings, monitor and analyze performance data, and consider key parameters when choosing an API monitoring tool. By following best practices such as setting clear objectives, establishing baseline metrics, monitoring key performance indicators, implementing real-time alerts, leveraging synthetic monitoring, analyzing historical data, and more, organizations can optimize their API monitoring strategy, minimize downtime, enhance performance, and ensure a seamless user experience.