Author here - opensourcing the tool we used for the last few months internally, to assist with visual checks and test automation. Under the hood, Appraise uses headless Chrome to take screenshots, so it can inspect anything that Chrome can render.<p>Appraise makes visual tests easy to compose and maintain, by letting people describe <i>what</i> they want something to look like instead of describing <i>how</i> to test it (eg 10 pixels left, this css color).<p>I'm currently working on a version that will allow running tests inside AWS Lambda, which should take care of the last mile of visual testing (so it's no longer slow).