Tool

Dockerfile Generator

Generate optimized, multi-stage Dockerfiles for your runtime. Pick a language, set the port, and copy.

Port:

# Dockerfile for Node.js
FROM node:20-alpine
WORKDIR /app

# Copy package files first (layer caching)
COPY package*.json ./
RUN npm ci --only=production

# Copy source code
COPY . .

RUN npm run build

EXPOSE 3000

CMD ["node", "dist/index.js"]

Dockerfile Best Practices

Order layers by change frequency - package dependencies first (slowest to change), source code last. Maximizes build cache usage.
Use multi-stage builds - compilers and build tools go in stage 1; only the runtime binary goes in production. Cuts image size by 5-10x.
Don't run as root - create a non-root user with `adduser` and switch with `USER`. Security 101.
Pin base image versions - `node:20-alpine` not `node:latest`. Reproducible builds save you from “works on my machine”.