3. The Build Pipeline & Deployment Model
3.1 How a deployment works
git push (or merge to main)
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Vercel detects framework → applies framework-specific build config
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Build (Turbopack / webpack / SWC compilation)
├── Static pages generated (SSG/ISR)
├── Route manifests generated
├── Function bundles compiled
└── Assets optimised (images, fonts)
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Build output deployed to:
├── CDN (static assets + ISR pages)
└── Vercel Functions infrastructure (serverless / Fluid)
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DNS updated → new deployment goes live (zero downtime)
Preview URL generated for every non-production deployment
3.2 Branch previews
Every push to any branch gets a unique Preview URL:
my-app-git-feature-auth-my-org.vercel.app
Preview deployments:
- Are isolated from production data (separate env vars)
- Have the same infrastructure as production
- Can be shared with stakeholders for review
- Automatically get comments from Vercel's GitHub/GitLab integration
- Support Draft Mode for CMS content preview
3.3 Deployment protection
Enterprise feature: Preview deployments can be protected behind:
- Vercel Authentication (team members only)
- Password protection
- Trusted IPs
3.4 Turbopack
Vercel's Rust-based bundler replacing webpack. Key facts for SE conversations:
- Up to 700× faster cold builds than webpack
- 10× faster HMR (Hot Module Replacement)
- Stable in Next.js 15 for development
- Incremental computation — only rebuilds what changed
- Enabled with
next dev --turbopack