What are the best application performance monitoring (apm) tools?

As of my last knowledge update in October 2023, several Application Performance Monitoring (APM) tools are widely recognized for their capabilities in monitoring, diagnosing, and optimizing application performance. Here are some of the best APM tools available:

1. **New Relic**: Offers comprehensive monitoring for applications, infrastructure, and user experience. It provides real-time insights and detailed performance metrics.

2. **Dynatrace**: Known for its AI-driven monitoring capabilities, Dynatrace provides full-stack observability, including application performance, infrastructure monitoring, and user experience.

3. **AppDynamics**: A Cisco product that provides deep insights into application performance, user experience, and business performance. It offers real-time monitoring and analytics.

4. **Datadog**: A cloud-based monitoring and analytics platform that provides APM, infrastructure monitoring, and log management. It integrates well with various cloud services and technologies.

5. **Splunk APM**: Part of the Splunk Observability Cloud, it offers powerful monitoring and troubleshooting capabilities, leveraging machine learning for anomaly detection.

6. **Elastic APM**: Part of the Elastic Stack, it provides performance monitoring for applications and integrates seamlessly with Elasticsearch for powerful data analysis.

7. **Prometheus with Grafana**: While Prometheus is primarily a metrics collection and alerting toolkit, when combined with Grafana, it can provide effective APM capabilities, especially for cloud-native applications.

8. **Sentry**: Primarily focused on error tracking and performance monitoring, Sentry helps developers identify and fix issues in real-time, providing insights into application performance.

9. **Raygun**: Offers error, crash, and performance monitoring for web and mobile applications, providing detailed reports and insights to help developers improve application performance.

10. **Honeycomb**: Focuses on observability and provides powerful querying capabilities to help teams understand complex systems and troubleshoot performance issues.

11. **Scout APM**: A lightweight APM tool that focuses on Ruby, Python, PHP, and Node.js applications, providing detailed performance insights and error tracking.

12. **Trace**: A newer entrant that focuses on distributed tracing and performance monitoring, particularly for microservices architectures.

When choosing an APM tool, consider factors such as the specific technologies you are using, the scale of your applications, integration capabilities, ease of use, and pricing. Each tool has its strengths and may be better suited for different environments or use cases.