Application Performance Monitoring (APM) is a set of tools and practices used to ensure that software applications run smoothly and efficiently. APM helps identify issues such as slow response times, errors, and bottlenecks in real-time, allowing developers and IT teams to address problems before they impact users. By collecting data on various performance metrics, such as response time, transaction volume, and resource usage, APM provides insights into how applications are performing. This information helps organizations optimize their applications, improve user experience, and maintain high levels of service reliability.