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Deployment

Multi-target deployment strategy proving runtime portability.

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What is it?

Multi-target deployment strategy proving runtime portability. Same codebase deploys to Vercel (serverless) and container platforms. SvelteKit's adapter system enables platform-agnostic builds.

What is it for?

  • Zero-config serverless deployment (Vercel)
  • Container-based deployment (Koyeb, Railway)
  • Testing runtime portability across platforms
  • Preview deployments per PR

Why was it chosen?

Target Runtime Platform Use Case
Serverless Node.js Vercel Zero-config, preview deploys
Serverless Bun Vercel Experimental (28% faster)
Container Bun Koyeb Native Bun, no cold starts

Vercel advantages:

  • Automatic framework detection
  • Git-based deployment with PR previews
  • Built-in edge caching, image optimization
  • Fluid compute: 99.37% of requests have zero cold starts

Container advantages:

  • Persistent runtime (no cold starts)
  • Full Node.js/Bun API access
  • Railway: 3-4x faster than Vercel in benchmarks
  • True free tier (Koyeb: no credit card)

Adapter selection:

Adapter Target
adapter-vercel Vercel (Node.js or Bun)
svelte-adapter-bun Bun containers
adapter-node Node.js containers

Known limitations

Vercel cold starts:

  • 2-3 seconds for heavy setups (GraphQL + Prisma)
  • Each cold start requires new database connections
  • Mitigated by Fluid compute (Pro/Enterprise)

Vercel lock-in:

  • Proprietary features (image optimization, ISR) create migration friction
  • SvelteKit adapter system provides better portability than Next.js
  • Can swap adapters without changing application code

Bun on Vercel:

  • SvelteKit not officially listed (Next.js, Express, Hono, Nitro only)
  • May break without warning
  • Test thoroughly before production

Container platforms:

  • Container sleep on free tiers causes cold starts
  • Requires Dockerfile knowledge

See vendors.md for pricing, free tier limits, and platform alternatives.

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