Locust is an easy-to-use, distributed, user load testing tool. It is intended
for load-testing web sites (or other systems) and figuring out how many
concurrent users a system can handle.

The behavior of each locust (or test user if you will) is defined by you and the
swarming process is monitored from a web UI in real-time. This will help you
battle test and identify bottlenecks in your code before letting real users in.

WWW: https://locust.io/