Knowledge Mark G
Hire Me

Free developer tool

Dockerfile Generator

Generate a multi-stage Dockerfile, .dockerignore and docker-compose.yml for Node.js, Python, .NET, Go or PHP.

  • No sign-up
  • Instant results
  • Runs in your browser

Your app

Stack
Options
docker-compose.yml

Files

Dockerfile
# syntax=docker/dockerfile:1

# --- build: install everything and compile
FROM node:24-alpine AS build
WORKDIR /app
COPY package.json package-lock.json ./
RUN npm ci
COPY . .
RUN npm run build

# --- runtime: production dependencies only
FROM node:24-alpine
WORKDIR /app
ENV NODE_ENV=production
COPY package.json package-lock.json ./
RUN npm ci --omit=dev && npm cache clean --force
COPY --from=build /app/dist ./dist
# The official Node images ship an unprivileged 'node' user.
USER node
EXPOSE 3000
CMD ["node", "dist/index.js"]

Build and run: docker build -t myapp . then docker compose up -d. Change every change-me password before deploying.

What makes a production Dockerfile

Every template here follows the same rules. Multi-stage builds compile in one image and copy only the result into a small runtime image, so compilers and dev dependencies never ship. Dependency files are copied first, so the slow install layer is cached and only rebuilt when package.json, requirements.txt or the .csproj changes. A non-root user runs the app, so a compromised process cannot rewrite the container. And a .dockerignore keeps .git, node_modules and .env files out of the build context - and out of the image.

Notes for each stack

  • Next.js needs output: "standalone" in next.config; the runtime image then carries only the traced server files.
  • .NET 8 and later images listen on port 8080 and include a non-root app user, selected with USER $APP_UID.
  • Go builds a static binary into a distroless image with no shell at all.
  • PHP uses the official Apache image with the document root moved to /public, which suits Laravel and Symfony.

docker-compose for local development

Add PostgreSQL, MySQL or Redis and the compose file wires it up with a health check, so the app only starts once the database is accepting connections. Change every placeholder password before you deploy. Putting nginx in front of the container? The nginx config generator writes the reverse proxy, and the cron generator handles scheduled jobs.

Questions people ask

What is a multi-stage Dockerfile?+

One with several FROM lines. Earlier stages build the app; the final stage copies only the build output into a clean, small image. Compilers, source code and dev dependencies stay behind.

Why run the container as a non-root user?+

If the app is compromised, the attacker gets that user's permissions, not root's. It is one line in the Dockerfile and many Kubernetes clusters refuse root containers anyway.

What should go in .dockerignore?+

Anything the build does not need: .git, node_modules, local build output, logs and especially .env files with secrets. A smaller context also makes builds faster.

Alpine or Debian slim?+

Alpine is smallest and works well for Node.js and Go. For Python, slim (Debian) is usually better: many Python packages ship pre-built wheels for Debian's glibc but must compile from source on Alpine's musl.

How do I build and run it?+

docker build -t myapp . builds the image; docker run -p 3000:3000 myapp runs it. With the compose file, docker compose up -d starts the app and its database together.