OpenJam’s rc-servers is a collection of re-implemented Robocraft web services. Robocraft was an online vehicle combat game where you build your own vehicle (robot) out of blocks and then fight others’ vehicles in a few different game modes. The official servers were shut down by FreeJam in January 2025.

These servers are intended for self-hosting but I’ve also got a reference instance running. There are also other instances running in Japan and the USA. I’ve been having a fun time reverse-engineering the expected server behaviour from the client as well as figuring out the niche communication protocols.