To join DrChrono as a developer, you first have to take a 1h40min programming test online. It uses several questions, which you solve by programming in one of several offered languages, then compile and test. High scores get contacted by the company.
After being contacted, they bring you in to do a "hackathon," regardless of which type of position. This is to let them know your skills and let you know how you can work with them. The hackathon lasts 3 days, with you basically experiencing what working there is like. They were very upfront that this does not guarantee a job there.