Athens [1] is an even better free and open source alternative, started by someone who was rejected [2] for a Clojure job at Roam! Athens was even accepted to YC [3].

[1] https://github.com/athensresearch/athens [2] https://news.ycombinator.com/item?id=26316793 [3] https://www.ycombinator.com/companies/athens-research