2026-03-12 - Vercel Fixes

Problem

The Vercel deployment was failing due to:

1. PNPM version mismatch (Lockfile was v10, package.json was v9.14).
2. Missing build script permissions in PNPM 10 (onlyBuiltDependencies).
3. Next.js output: 'export' mode conflicting with API routes on Vercel.
4. SolidStart/Nitro building a generic Node server bundle instead of the Vercel-specific .vercel/output format, causing a 404 on all routes.

Solution

PNPM 10 Migration

Updated package.json to specify pnpm@10.0.0. This ensures the environment matches the lockfile exactly.

build scripts

Added @parcel/watcher, esbuild, and sharp to pnpm.onlyBuiltDependencies in the root package.json.

Dynamic Next.js Configuration

Updated apps/docs/next.config.mjs to check for process.env.VERCEL.

• If on Vercel: output is undefined (standard SSR/ISR mode), enabling API routes.
• If not on Vercel: output is export, for GitHub Pages compatibility.

Node Engines

Standardized all engines fields to node: >=22.

Nitro Vercel Preset

Updated apps/web/vite.config.ts to pass server: { preset: "vercel" } to solidStart() when the VERCEL environment variable is set.

Why this matters: Nitro (the server used by SolidStart) supports multiple deployment targets via "presets." Each preset produces a different output format. Without preset: "vercel", Nitro builds a plain Node http.createServer bundle in .output/. Vercel does not know how to run this — it expects a .vercel/output/ directory with a specific config, functions, and static file layout. Setting the preset instructs Nitro to produce exactly that format, which Vercel can then interpret and deploy as serverless functions.

The VERCEL env var is automatically set to "1" on all Vercel build machines, so the switch is transparent — local development and other CI environments continue to use node-server.