Hey! Good question, we're still working out the details on pricing but I want it to be very reasonable, simple and transparent for people. Just need some time to work through with a few initial beta testers. Stay tuned!
I think they might only do live sites, the thing about Percy is that it can be integrated earlier into your feature/browser tests for all pages, even those behind logins.
Actually it's all home grown, right now it renders the page and screenshots in Firefox 38 ESR and then the actual diff image is produced by imagemagick's compare function, with some special things around it to handle edge cases with width/height differences and some others.
Are you an one man army? Congrats! :) This is great. How do you plan to react to potential changes in rendering engines? Would those be shown as test failures as well?
Great question! And yes. :) My plan at the moment for that is, because I know which browser exactly it was rendered in originally, I can put a notice at the top of the page to say something like "We just upgraded our rendering browser! The diffs below might because of that and not because of a change you made." -- and then after that one build, things would be back to normal.
