Stampede is a load testing library that speaks Phoenix Channels and LiveView, with scenarios in plain Elixir. 1.2 adds –find-limit, which raises the load step by step until your thresholds break and tells you the most users your app held, plus a README badge with the result, Markdown comparisons for pull requests, and a warning when the load test itself is too busy to trust.

I tested it on AWS: one stock Phoenix server with 4 cores and 32 GB held 400,000 Channels users with 0 errors, joins in 12ms at p95, and 24% CPU. Everything to rerun it is in the repo.

https://github.com/mandar1045/stampede