I needed to crawl sitemaps, create snapshots in three device sizes (mobile, tablet and desktop) and compare my snapshots with their previous versions. I ended up creating this tool <a href="https://github.com/raminv80/webTimeMachine" rel="nofollow">https://github.com/raminv80/webTimeMachine</a> it is not perfect but does the job. I might continue improving it if others find it useful.