Docker Multi-Stage Build for Next.js - Optimize Image Size

Problem

A naive Docker build for Next.js includes the entire node_modules directory, resulting in images over 1GB. DevDependencies bloat it even further.

Solution

# Stage 1: Install dependencies
FROM node:22-alpine AS deps
WORKDIR /app
RUN apk add --no-cache libc6-compat
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: Run (minimal image)
FROM node:22-alpine AS runner
WORKDIR /app
ENV NODE_ENV=production
RUN addgroup --system --gid 1001 nodejs
RUN adduser --system --uid 1001 nextjs
COPY --from=builder --chown=nextjs:nodejs /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"]

Key Points

Set output: 'standalone' in next.config.js to generate .next/standalone. Without this, stage 3 won’t work.
The 3-stage split (deps → builder → runner) ensures only production-necessary files end up in the final image.
Creating a non-root user with adduser is a security baseline. Even if the container is compromised, there’s no root access.