Build Strategies
Build your web service from Git using Railpack auto-detection or a Dockerfile.
Last updated: June 19, 2026
Build Strategies
When the source is a Git repository, you choose how the image is built. Switch between strategies with the Build Method toggle.
| Strategy | What it does |
|---|---|
| Railpack | Auto-detects your language and builds a production image. Supports Node.js, Python, Go, Ruby, Java, PHP, Rust and more. The Stack Detection card shows a live preview of what Railpack found in your repo, including the detected port. |
| Dockerfile | Uses the Dockerfile in your repository. A separate Dockerfile Path field appears, defaulting to Dockerfile. Change it if yours sits elsewhere. |
The optional Project Root field lets you build a subdirectory of a monorepo. Leave it empty to build from the repository root.
Builds run on a fresh, ephemeral build machine and produce a container image that lowcloud pushes to your project's private registry. The container in your project pulls the image from there.
Build & Output Settings
With Railpack, lowcloud auto-detects the install, build, and start commands as well as the port. You can override any of them: open Build & Output Settings and turn on the Override toggle next to the field.
| Field | What it does |
|---|---|
| Install Command | Command that installs your dependencies (e.g. npm ci). |
| Build Command | Command for the build step (e.g. npm run build). |
| Start Command | Command that starts your application (e.g. npm run start). |
| Application Port | Port your application listens on inside the container. |
Without an override, lowcloud uses the auto-detected values.