Loader.io is a free load testing service that allows you to stress test your web-apps & apis with thousands of concurrent connections.

k6 Open Source is designed for load testing. Extensible to support other types of testing.

Datadog is a cloud-based monitoring and analytics platform that provides observability and security for cloud-scale applications

The Complete Continuous Testing Platform Any test. Any device. App quality without limits.

Gatling is a powerful open-source load testing solution that integrates with your development pipeline. It includes a web recorder and colorful reports.

Uptime Kuma is an easy-to-use self-hosted monitoring tool.