Built by the people who host game servers for a living
Crux is the game backend from Supercraft, a game server hosting company. We spend our days running dedicated servers for other people's games - Crux is the backend layer we built alongside that infrastructure: auth, player data, leaderboards, matchmaking, server registry, and live config, over plain HTTP and JSON.
One team, both layers
The same engineering team operates the Supercraft hosting fleet and the Crux backend. That matters for one practical reason: the failure modes of live multiplayer games - full disks, noisy neighbours, weekend traffic spikes, game-patch stampedes - are our day job, not a theoretical exercise.
Open where it counts
The client SDKs are MIT-licensed and public: github.com/supercraft-host/crux and crux-sdk on npm, covering Godot, Unity, Roblox, and JavaScript. The hosted backend itself is a proprietary managed service, but its HTTP API is openly documented (OpenAPI spec) and everything you store is readable back out through it - see the sunset & export guarantee for the written version.
Where we are honest about being small
Crux launched in 2026 and we do not have public case studies yet - we would rather say that plainly than invent logos. What we can show today: the API reference, the two-minute quickstart, a free Dev tier with every feature, and a support channel where the people answering are the people who wrote the code.
Talk to us
Email contact@supercraft.host - it is read by engineers, not a ticket router. Or join the Discord for quickstart help and roadmap questions. If you are writing about game backends and need a source, the same address works.
The inspectable parts matter more than an about-page promise.
We do not have a logo wall or public case studies yet. Check the running service, the API contract, the MIT SDKs, and the written exit path instead.
Live API status
A live check of the hosted API right now. No made-up uptime percentage and no hidden demo environment.
Check current statusPublic API contract
The hosted HTTP surface is documented as OpenAPI. Inspect the wire format before choosing an SDK or writing an adapter.
Open the specMIT client SDKs
The JavaScript, Godot, Unity, and Roblox client SDK source is public. The hosted backend itself remains a managed proprietary service.
Inspect the SDK sourceDocumented exit path
Read what is exportable today and the written commitment for advance notice plus an export window if the hosted service winds down.
Read the exit guaranteeAPI explorer
The generated docs are served from the same OpenAPI contract used to keep the implementation and documentation aligned.
Open API docs