LeashLeash

Deploy Next.js

Leash detects Next.js automatically from your package.json. Before deploying, it runs a preflight build locally to catch errors early.

Auto-Detection

If your project has a package.json with a next dependency or a next.config.* file, Leash automatically selects the Next.js build strategy.

Terminal

$ cd my-nextjs-app

$ leash deploy

✓ Detected Next.js 15

✓ Preflight build passed

✓ Image built and pushed

✓ Deployed successfully!

→ https://my-nextjs-app-arvin.un.leash.build

Preflight Build

Leash runs npm run build locally before uploading your code. This catches errors fast and saves time.

What the preflight checks

  • Runs npm run build locally
  • Catches type errors before remote build
  • Validates that the build output is correct

Common Issue: TypeScript Target

Build fails with syntax errors?

Your tsconfig.json may be targeting ES5, which causes issues with modern syntax. Update it to a modern version:

{
  "compilerOptions": {
    "target": "ES2017",
    "module": "esnext"
  }
}