Docker multi-stage build for Next.js

Here's a production-ready multi-stage Dockerfile for Next.js standalone:

dockerfileCopy
# Stage 1: Install dependencies
FROM node:20-alpine AS deps
WORKDIR /app
COPY package.json package-lock.json ./
RUN npm ci

# Stage 2: Build
FROM node:20-alpine AS builder
WORKDIR /app
COPY --from=deps /app/node_modules ./node_modules
COPY . .
ENV NODE_ENV=production
RUN npm run build

# Stage 3: Production runner
FROM node:20-alpine AS runner
WORKDIR /app
ENV NODE_ENV=production

RUN addgroup --system --gid 1001 nodejs
RUN adduser --system --uid 1001 nextjs

COPY --from=builder /app/.next/standalone ./
COPY --from=builder /app/.next/static ./.next/static

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

Key points:

• 3 stages keep the final image small (~200MB vs ~1GB)
• standalone output means no node_modules needed at runtime
• Non-root user (nextjs) for security
• Static assets must be copied separately (standalone doesn't include them)

Make sure next.config.mjs has output: "standalone".