Prior to working at Etsy he spent almost four years at Wayfair, where he led the team that converted the primary tech stack to PHP/Lighttpd/FreeBSD. He started and organizes the Boston Web Performance Meetup Group, and he contributes to a few open source projects, including the HTTPArchive and CSSLint. Jonathan blogs regularly at jonathanklein.net and can be found on Twitter at @jonathanklein.