We kept watching the same thing happen on shipping teams. The team would push a Friday-night fix, the deploy would go green in CI, every Playwright test would pass, every screenshot diff would come back clean. Then on Monday morning a customer would DM a screenshot of the signup button cut in half on a Pixel 5 — and nobody on the team could reproduce it on their laptop.

The reason is depressing once you see it: "works on my machine" is even more true now than it was in 2010. Modern CI runs Chrome in a Linux container at a desktop viewport. Lighthouse runs Chrome in a Linux container at a simulated mobile viewport. Visual regression tools run Chrome in a Linux container at a recorded viewport. All of them are simulating what a phone sees. None of them are a phone.

Canaryflux takes the opposite shape of constraint. Instead of asking the team to write tests, we ask the team to paste a URL. The scanner opens it on a parallel device matrix — iPhone 15 Pro, Pixel 8, Galaxy S25 Ultra, iPad Pro, Desktop Chrome — captures full-page screenshots, console errors, and network failures, then sends the captures to AI vision with a tightly-tuned QA prompt that grades each finding by severity.

Read the full post at canaryflux.com/blog/why-we-built-canaryflux.