Commit

Level one is just where everyone starts. Rank is XP based, and your XP comes from 10 per commit, 15 per day in your longest streak, 5 per star received, 5 per reply to another developer, and 2 per star you give. So publish a commit or two and you climb. I do not know the exact XP cutoff for each level, sorry. See "Achievement badges and XP" on /dev/null.