Bundle Baseline — 2026-07-07

Reference numbers for the performance TODO (performance-improvements-todo.md). Re-measure against this after each work block.

Build: npm run build:analyze (Next.js 16.2.10, webpack, production). Note: Next.js 16 removed the per-route size / First Load JS columns from next build output (deemed inaccurate with RSC). The numbers below are computed from .next/build-manifest.json and the emitted chunk files; analyzer reports live in .next/analyze/ (regenerate with the same command).

Shared first-load JS (every app route ships this)

From build-manifest.json → rootMainFiles:

Chunk	Raw	Gzipped
webpack-*.js	6.7 KB	3.8 KB
4bd1b696-*.js (React/framework)	195.2 KB	62.1 KB
3794-*.js (shared app/vendor)	217.5 KB	59.8 KB
main-app-*.js	0.5 KB	0.2 KB
Total	420.0 KB	125.9 KB

Whole client build: 243 JS chunks, 3,206 KB raw.

Largest chunks (raw, on-demand unless noted)

Chunk	Raw	Contains
8600-*.js	757.4 KB (266.8 KB gz)	monaco-editor, sanitize-html, handlebars
1683-*.js	370.2 KB (109.7 KB gz)	libphonenumber-js, jszip
1863-*.js	252.6 KB	qrcode, handlebars
3794-*.js	217.5 KB	shared (in first load)
4bd1b696-*.js	195.2 KB	React framework (in first load)
framework-*.js	185.3 KB	React framework
5205-*.js	137.7 KB	—
main-*.js	129.9 KB	webpack runtime + chunk map
polyfills-*.js	110.0 KB	—
574-*.js	94.6 KB	@clerk/nextjs
9055-*.js	70.3 KB	@mui/material

Findings against the TODO gates

• 2.2 Monaco: chunk 8600 is async/on-demand — not in rootMainFiles and not referenced by any route's page_client-reference-manifest; only the webpack runtime chunk map in main-*.js knows its URL. Monaco is bundled locally (served from /_next/static/chunks/), not CDN. The barrel export does not put Monaco in any route's first load → restoring next/dynamic is not needed for first-load reasons. Caveat: 8600 also carries sanitize-html + handlebars; whichever route imports those client-side pulls the whole 757 KB chunk.
• 2.3 Clerk localizations: not present in any client chunk — the ~50 locale imports in [locale]/layout.tsx cost server module evaluation and RSC payload only (a single locale object crosses to the client). Client bundle is unaffected; the per-locale import remains a server-side win.
• 2.4 Small deps: i18n-iso-countries — not in any client chunk (server-only, confirmed). libphonenumber-js + jszip — client-side in async chunk 1683 (370 KB raw); subset entry point for libphonenumber is the candidate. qrcode, handlebars, sanitize-html — present in client chunks (1863, 8600), contrary to the "stay server-only" assumption; worth tracing which client imports pull them.