Deploy Overview
Leash auto-detects your framework, runs preflight checks locally, builds a container image, and deploys it to the cloud. No config files, no YAML, no infrastructure to manage.
Auto-Detection
When you run leash deploy, the CLI inspects your project and picks the right build strategy automatically.
| File | Framework |
|---|---|
next.config.* | Next.js |
requirements.txt (with flask) | Flask |
package.json (with start script) | Node.js / Express |
go.mod | Go |
Dockerfile | Docker |
index.html | Static HTML |
Preflight Checks
Before uploading anything, Leash runs your build locally to catch errors early. This saves time by surfacing type errors, missing dependencies, and misconfigured build scripts before the remote build even starts.
What the preflight checks
- Runs
npm run build(or framework-equivalent) locally - Catches TypeScript type errors before remote build
- Validates that the build produces the expected output
- Reports clear, actionable error messages if something fails
Preflights are always on. If the app does not build locally, Leash stops before uploading anything so you do not spend time or credits on a broken deploy.
Deploy Flags
Customize your deploy with optional flags passed to leash deploy.
| Flag | Description |
|---|---|
--html | Deploy a single HTML file as a static site |
URL Scheme
Every deployed app gets a unique URL under the un.leash.build domain. The format is:
https://{app-name}.un.leash.build
The app name defaults to the directory name but can be overridden with --name. All apps are served over HTTPS automatically.