[inglor]

We use both Testim.io and Playwright for performance testing.

I work at Microsoft but at a completely unrelated team and while I know some of the folks who work on playwright I have no official affiliation and my opinions represent my own and not my employer's.

Playwright is great for this sort of thing! All we do is run the same test with two variants (before/after the change) and run a student t-test (well, a welch t-test but close enough).

It's ±50 LoC and as long as you're fine with running the test enough times to get statistical significance Playwright works quite well for this