Preview Mode

Preview mode allows running all 4 Next.js applications (login, doceditor, management, sdk) as pre-built production bundles in a single orchestrated server, instead of running them in development mode via webpack-dev-server.

This significantly reduces startup time and memory usage during local development.

How it works

The deploy:preview script builds each Next.js app in standalone mode (output: "standalone") and merges their outputs into a single publish/web/apps/ directory with shared node_modules.

At runtime, server.js starts each app as an isolated child process on its original port (login:5011, doceditor:5013, management:5015, sdk:5099) and acts as an HTTP reverse proxy on port 5055, routing requests by URL prefix.

The client SPA (webpack build) is deployed separately to publish/web/client/ and served by nginx in Docker, or locally via npx serve -s -p 5001.

Browser -> nginx (8092) -> apps server (5055) -> child processes
                |                                  |-- login (5011)
                |                                  |-- doceditor (5013)
                |                                  |-- management (5015)
                |                                  +-- sdk (5099)
                +-> client static (5001)

Quick start

1. Start the backend

cd server/common/ASC.AppHost
dotnet run --launch-profile frontend-dev

2. Build and deploy

cd client
pnpm deploy:preview

This will:

• Build all 4 Next.js apps with output: "standalone"
• Deploy the client (webpack) app
• Merge standalone outputs into publish/web/apps/
• Copy public assets and minify locales

3. Start the client static server

cd publish/web/client
npx serve -s -p 5001

4. Start the apps server

cd publish/web/apps
node server.js --app.port=5055 --app.hostname=127.0.0.1

The portal is available at http://localhost:8092.

Docker preview

In Docker, nginx serves the client static files directly and proxies SSR requests to the apps server. No separate npx serve is needed.

Architecture

Files

File	Description
common/scripts/preview/deploy.js	Build-time script that merges standalone outputs into publish/web/apps/
common/scripts/preview/server.js	Reverse proxy server — forks child processes and routes by URL prefix
common/scripts/preview/server.prod.js	Production entry point — sets env vars, parses CLI args, requires server.combined.js
common/scripts/preview/app-worker.js	Child process wrapper — reads Next.js config, patches trustHostHeader, starts the app

Deploy output

publish/web/
|-- apps/
|   |-- node_modules/              # Merged from all 4 standalone builds
|   |-- packages/
|   |   |-- login/.next/           # Login build output + static assets
|   |   |-- doceditor/.next/       # DocEditor build output + static assets
|   |   |-- management/.next/      # Management build output + static assets
|   |   |-- sdk/.next/             # SDK build output + static assets
|   |   +-- shared/                # Shared workspace dependency
|   |-- libs/
|   |   +-- ui-kit/                # UI kit workspace dependency
|   |-- server.js                  # Entry point (= server.prod.js)
|   |-- server.combined.js         # Proxy server (= server.js from source)
|   +-- app-worker.js              # Child process wrapper
+-- client/                        # Client SPA (webpack build)

Why process-per-app

Next.js uses globalThis singletons (Symbol.for('next.server.manifests'), Symbol.for('@next/router-server-methods')) that get corrupted when multiple apps share a single Node.js process. Running each app in its own child process provides full isolation (separate globalThis, module cache, AsyncLocalStorage) while still sharing disk space through the merged deploy output.

Environment variables

Variable	Default	Description
PORT	5055	Main proxy server port
HOSTNAME	0.0.0.0	Main proxy server bind address
API_HOST	http://localhost:8092	Backend API URL (passed to child processes for SSR)
NODE_ENV	production	Node environment

Comparison with other modes

	pnpm start	pnpm start:lite	Preview mode
Apps	5 (client + 4 SSR)	3 (client + login + doceditor)	5 (client + 4 SSR)
Build required	No (dev mode)	No (dev mode)	Yes (pnpm deploy:preview)
Startup time	Slow (webpack)	Medium	Fast (pre-built)
Hot reload	Yes	Yes	No (rebuild required)
SSR apps mode	Development	Development	Production
Client app mode	Development	Development	Production (static via nginx)