Hi! It's technically possible to test your localhost though it's a bit of work with ngrok. What we're seeing more and more of with our customers is they stand up ephemeral environments for each PR, or each merge, and then use Reflect's hostname and URL overrides at run time to target their code changes with the tests they already recorded against prod or staging. We've worked with Release W20 (https://releaseapp.io/) in the past to demonstrate running Reflect tests against each PR. I know it's not exactly what you're looking for, but similar in spirit, I think.
Update: reading through this thread and a bit web search resulted in the following list:
https://ghostinspector.com https://www.testim.io https://www.katalon.com https://www.cypress.io https://github.com/dequelabs/axe-core https://www.mabl.com https://preflight.com
> We’re taking a new approach by loading the site-under-test inside of a VM in the cloud rather than rely on a locally installed browser extension.
But how would I record and test things locally? I.e. I would need a public setup right at the beginning.