Free Minecraft servers that sleep when nobody plays and wake when someone joins.
Java and Bedrock, on Pumpkin.

kurbis.host · Self-hosting · Development · AGPL-3.0

Kurbis is the hosting platform behind kurbis.host. Every account gets one server. A server costs nothing while nobody is on it: after five idle minutes it saves, snapshots its world to object storage and gives its memory back. The next player who joins its address wakes it. They wait in a lobby while the world is restored and the server starts, then the game transfers them to it by itself.

There's no sign-up form. Joining a free address with a verified Minecraft account claims it and creates that player's account and server. Google or Discord can be linked later to manage the server from the web panel.

 Java / Bedrock client
          │  join  name.kurbis.host
          ▼
 ┌─────────────────┐  route, wake    ┌───────────────────┐
 │     Gateway     │ ──────────────▶ │   Control plane   │──▶ PostgreSQL
 │ hostname proxy, │                 │ accounts, servers │
 │ waiting lobby   │                 │ placement, locks  │
 └────────┬────────┘                 └─────────┬─────────┘
          │ transfer when ready                │ assignments
          ▼                                    ▼
 ┌─────────────────────────────────────────────────────┐
 │ Worker: runs isolated Pumpkin servers (Docker or    │──▶ S3-compatible
 │ native), restores and publishes world snapshots     │    object storage
 └─────────────────────────────────────────────────────┘

A server moves through sleeping → queued → restoring → starting → online → stopping → snapshotting → sleeping.

• Waking takes the lifecycle lock, reserves worker capacity, restores the latest valid snapshot, starts Pumpkin, checks readiness, then publishes the route.
• Sleeping stops new routes, saves the world cleanly, validates a new snapshot, then releases the worker's resources.

Lifecycle operations hold a lock in PostgreSQL, so concurrent joins start a server only once, and a lost worker's servers recover from their last snapshot on another worker.

• Wake on join, sleep when idle. Java 26.3 hostname routing, a waiting lobby and native transfer to the backend once it's up.
• Accounts from Minecraft identities. Verified Java and Bedrock players register or resume an account just by joining. Google or Discord sign-in can be linked, and merging accounts keeps every world.
• Web panel. Lifecycle controls, settings, players and whitelist, logs, snapshots and plugins, with live updates over SSE.
• In-game management. OP-only /kurbis opens a chest-menu panel and can hand out a one-use login link scoped to that server.
• Plugins. Install free plugins from the Pumpkin market or upload your own WebAssembly component. Changes load into a running server without a restart.
• AI assistant (optional). OP-only /ai runs a model through Anthropic's API or any OpenAI-compatible endpoint, with per-server and per-account monthly budgets.
• Pumpkin previews (optional). Every open pull request on Pumpkin gets a joinable preview address. Its code is compiled in a sandbox with no network.
• Isolation. Rootless Docker per server, an internal-only network, and a firewall that admits only the gateway.

You need Rust 1.98.1, Node.js with pnpm 11.2.2, and PostgreSQL. Docker is only needed for container deployments; local development runs on macOS or Linux directly.

Just the web panel and landing page, with no backend:

cd web
pnpm install --frozen-lockfile
pnpm run dev

Then open http://localhost:3000. The panel itself (/app) needs the control plane.

The whole stack in a tmux dashboard (also needs tmux, Git and CMake). The first run writes a private .env for you to fill in:

./start.sh native debug

Development covers running the control plane against a local OAuth fixture, native workers and the test suites. Self-hosting covers the Docker deployment, TLS, firewalling and object storage.

TEST_DATABASE_URL=postgres://localhost/kurbis_test \
  tools/run_bounded_build.py --memory-bytes 10737418240 -- \
  cargo test --locked --all-targets -- --test-threads=1

Point it at a disposable database; the tests bootstrap their own schema in it. The browser suite runs the real panel, API and PostgreSQL in Playwright; see its README.

• Development: local stack, builds, tests
• Self-hosting: deployment modes, networking, TLS, releases
• Configuration: OAuth providers, the AI assistant
• Pumpkin previews: the CI preview service
• Native host development and the hosted Pumpkin runtime
• Control-plane workers: background tasks and supervision

Issues and pull requests are welcome. Run the tests above before opening a pull request, and keep changes focused. By contributing you agree that your contribution is licensed under the AGPL-3.0.

Kurbis is free software under the GNU Affero General Public License v3.0. If you run a modified version as a service, you must offer its users the source code of your version.

The Pumpkin integration in runtime/pumpkin/ modifies Pumpkin and stays under Pumpkin's GPL-3.0.

Kurbis is not an official Minecraft or PumpkinMC product. It is not approved by or associated with Mojang or Microsoft.