Applied for Publica, a company in SF that was acquired by IAS and it seems all recruitment is now handled by IAS as well. Company uses the HackerRank platform for screening. Practice on HackerRank before attempting. Familiarize yourself with the IDE and the way questions are framed. HackerRank is notorious for having badly framed questions and test cases.

First step of interview process is doing some coding challenges on Coderbyte. Must be completed in Javascript or Golang but doesn't clarify if Typescript is allowed even though that's what's listed as a req on the job posting.