Multi-stage Docker builds cut Node image size from 1 GB to a fraction

Most inherited Node.js Docker images exceed one gigabyte, even though the actual application may occupy only around 40 MB, with the remainder comprising compilers, dev dependencies, npm cache, and source files. This bloat slows deployments, increases security scan times, and widens the attack surface for vulnerabilities. Multi-stage Docker builds address this by using multiple FROM instructions, allowing developers to compile the app in an early stage and copy only the necessary production artifacts into a leaner final image. The final image can be based on a minimal variant like node:20-slim or a distroless image, and should install only production dependencies via npm ci --omit=dev rather than copying node_modules from the build stage. Proper layer ordering — copying lockfiles before source code — also preserves Docker's build cache, keeping repeated builds fast.