How to Build Only Affected Projects in a Monorepo on Vercel

Optimizing Monorepo Deployments on Vercel: A Case Study of utities.online

The Challenge

Large Monorepo projects—especially those hosting multiple independent web apps—often face a common deployment inefficiency on Vercel: even minor changes to a single subproject trigger a full rebuild and redeployment of the entire repository. This not only wastes valuable build resources but also significantly slows down deployment times, hampering developer productivity.

Case Study: utities.online Project Structure

Directory Layout

The utities.online project is a typical Monorepo managed with pnpm workspaces, hosting several standalone web apps under the utities.online domain ecosystem:

├── package.json
├── pnpm-lock.yaml
├── pnpm-workspace.yaml
└── packages/
    ├── altitude/          ← Altitude measurement tool
    ├── auto-trim-image/   ← Automatic image cropping tool
    ├── image-compare-pro/ ← Image comparison tool
    ├── logo-dash/         ← Logo generation tool
    ├── shared-ui/         ← Shared UI component library
    └── video-splitter/    ← Video splitting tool

Each app is deployed to a unique subdomain (e.g., altitude.utities.online, logo.utities.online), while the main website lives at www.utities.online.

Shared UI Dependencies

Subprojects reference the shared UI library via pnpm’s workspace protocol:

json
// Example package.json for a subproject
{
  "dependencies": {
    "shared-ui": "workspace:*"
  }
}

All subprojects use a similar vercel.json configuration:

json
{
  "buildCommand": "pnpm generate",
  "outputDirectory": "dist/static",
  "installCommand": "pnpm install",
  "framework": "vite"
}

The Solution: Smart Deployment Skipping

Vercel offers a powerful feature to skip builds when no relevant changes are detected. For multi-subdomain projects like utities.online, this is a game-changer.

How to Enable

1. Log in to the Vercel dashboard and navigate to your project.
2. Go to the "Git" or "Deployments" tab in the project settings.
3. Enable the option: "Skip deployments when there are no changes to the root directory or its dependencies".
4. Save the changes.

This setting instructs Vercel to analyze code changes intelligently. If only one subproject is modified, only that subproject will be rebuilt and redeployed to its corresponding subdomain.

Results

After enabling smart deployment skipping, the utities.online project sees dramatic improvements:

• Isolated Updates: Changes to a single subproject trigger a rebuild only for that subproject.
• Dependency-Aware Builds: Updates to the shared UI library trigger rebuilds only for dependent subprojects.
• Resource Efficiency: Build resources are used optimally, and deployment times are slashed.
• Faster Iteration: Teams can deploy updates to utities.online faster, boosting productivity.

Why It Matters

For large Monorepos like utities.online, this simple configuration change transforms the deployment workflow. It ensures that each subdomain updates independently and efficiently, making the most of Vercel’s infrastructure.

Key Takeaway: By leveraging Vercel’s built-in intelligence, you can optimize Monorepo deployments—saving time, resources, and developer frustration.

Have you faced similar Monorepo deployment challenges? How did you solve them?