How do I deploy a Next.js app with Docker using a small standalone image?

Use output: "standalone" and a multi-stage build. Next traces the needed files into .next/standalone.

// next.config.ts
import type { NextConfig } from "next";
const config: NextConfig = { output: "standalone" };
export default config;

# Dockerfile
FROM node:22-alpine AS deps
WORKDIR /app
COPY package.json package-lock.json ./
RUN npm ci

FROM node:22-alpine AS build
WORKDIR /app
COPY --from=deps /app/node_modules ./node_modules
COPY . .
ARG NEXT_PUBLIC_SITE_URL
ENV NEXT_PUBLIC_SITE_URL=$NEXT_PUBLIC_SITE_URL
RUN npm run build

FROM node:22-alpine AS run
WORKDIR /app
ENV NODE_ENV=production PORT=3000 HOSTNAME=0.0.0.0
RUN addgroup -S app && adduser -S app -G app
COPY --from=build /app/public ./public
COPY --from=build --chown=app:app /app/.next/standalone ./
COPY --from=build --chown=app:app /app/.next/static ./.next/static
USER app
EXPOSE 3000
CMD ["node", "server.js"]

Key points

• public and .next/static are not copied into standalone automatically; copy them as shown.
• Run with node server.js, not next start.
• NEXT_PUBLIC_* must be present at build time (build args). Server secrets are passed at runtime: docker run --env-file .env.production -p 3000:3000 image.
• HOSTNAME=0.0.0.0 is needed so the container accepts traffic from outside.
• Add a .dockerignore with node_modules, .next, .git, .env*.
• Put Nginx or Caddy in front for TLS and gzip, and forward X-Forwarded-* headers.
• Native modules such as sharp work on Alpine for current Next versions; if you hit libc issues use node:22-slim.

Pitfall: images that do not set HOSTNAME listen only on the container's own hostname and health checks fail.

The Dockerfile and Compose generator can scaffold a similar setup.