After working on APIs from FMCSA, it's not easy, because they have no customer. My org was required by law to meet their deadlines. They setup a test api 2 months after the deadline. Their backup method of sending the data was another 2 weeks after that. It was through soap because they said that was the most secure. We had a team contact them about ambiguity in their documentation and it took 6 months to get a reply.