How to use the Dockerfile Generator
1. Select your runtime/framework from the tabs.
2. Set the port your app listens on and optionally override the start command.
3. Copy the generated Dockerfile and save it in your project root.
What is it?
Docker containers package your application with all its dependencies, ensuring consistent behavior across development, staging, and production environments. A Dockerfile defines how to build a container image for your app.
Multi-stage builds (used in the Go and React templates) produce smaller images by separating the build environment from the runtime environment. Alpine-based images are recommended for production — they're tiny (5MB vs 900MB for ubuntu) and have a smaller attack surface.
Example
Language: Node.js · Port: 3000 · Multi-stage: Yes
FROM node:20-alpine AS builder WORKDIR /app COPY package*.json ./ RUN npm ci --only=production FROM node:20-alpine WORKDIR /app COPY --from=builder /app/node_modules ./node_modules COPY . . EXPOSE 3000 CMD ["node", "server.js"]
Multi-stage builds reduce final image size by only copying production artifacts. Alpine images are ~5MB vs ~900MB for full Node.
Benefits
Start from a Dockerfile that follows production best practices
Non-root user, minimal base image, correct COPY order for layer caching — included by default rather than discovered through trial and error.
Generate multi-stage Dockerfiles that keep images small and secure
Multi-stage builds separate the build environment from the runtime image — dramatically smaller final images with fewer vulnerabilities.
Correct layer caching order from the first line
Copying package.json before source code ensures dependency layers are cached — turning multi-minute rebuilds into seconds for unchanged dependencies.
Dockerfiles for Node.js, Python, Go, Java, and other runtimes
Each language has specific patterns for efficient builds and small images — the generator applies the right pattern for your runtime.
Frequently asked questions
What is a multi-stage build?
Multi-stage builds use multiple FROM statements. The first stage builds the app (with all dev tools), and the second stage copies only the built output into a clean, minimal image. This dramatically reduces final image size.
Should I use alpine or slim base images?
Alpine is the smallest (5MB) but uses musl libc instead of glibc, which can cause compatibility issues. Slim images are Debian-based (smaller than full Debian) and more compatible. Choose based on your dependencies.