Bert Belder began their career in 2007 as a Software Architect for Aanenuitbesteden.nl BV. In 2011, they became a Node.js core developer for Rackspace, the Open Cloud Company, and Cloud9 IDE. In 2013, they co-founded StrongLoop, Inc., where they served as a Node.js core developer. In 2015, they joined IBM as an STSM - Node.js core developer. In 2018, they founded Deno and currently serves as the CTO.