Generate a production-ready Dockerfile in seconds
A good Dockerfile is mostly boilerplate that is easy to get subtly wrong: copying lock files before source so layers cache, splitting build and runtime stages, dropping root, adding a health check and keeping .git and .env out of the image. This Dockerfile generator writes all of that for Node.js, Python, Go, Java, PHP, Ruby, Rust and static sites served by nginx, following the patterns in Docker’s own best-practice guide.
Choose the runtime and package manager — npm, pnpm, Yarn or Bun; pip, uv or Poetry; Maven or Gradle; Composer; Bundler; Cargo — set the port, working directory, environment variables, start command and health-check path, and tick the options you want: multi-stage build, non-root user, HEALTHCHECK, Alpine or slim base images, BuildKit cache mounts and a tini init process. A matching .dockerignore and the build/run commands are generated alongside.
The templates are assembled in your browser; nothing about your project is uploaded.
How to use the Dockerfile Generator
- Pick the Language / runtime. Sensible defaults for the base image tag, port, environment and start command load automatically.
- Choose the Package manager / build tool the project uses, so the right lock file and install command are copied in.
- Set the Exposed port, Working directory, Start command (leave blank for the default) and Healthcheck path; add
KEY=valueenvironment lines. - Toggle Multi-stage build, Run as non-root user, HEALTHCHECK, Alpine / slim base, BuildKit cache mounts and Init process (tini).
- Copy or download the Dockerfile and the
.dockerignore, then run the printeddocker buildanddocker runcommands.
Dockerfile Generator features
Multi-stage by default
Build tools, compilers and dev dependencies stay in the first stage; the final image contains only the runtime and the compiled output. Go and Rust can even ship a single static binary on a distroless or Alpine base.
Layer-cache-friendly ordering
Manifest and lock files are copied and installed before the rest of the source, so dependency layers are reused until the lock file changes. BuildKit --mount=type=cache keeps package caches between builds.
Secure defaults
A dedicated non-root user (node, www-data, nonroot or a created app user), no secrets baked in, and a .dockerignore that excludes .git, .env, logs and local build output.
Health checks that work without curl
Node and Python images use their own runtime for the probe, Alpine images use wget, Debian-based ones curl, so docker ps and orchestrators can see whether the app is really up.
Eight stacks, one form
Node (npm/pnpm/Yarn/Bun), Python (pip/uv/Poetry), Go, Java (Maven/Gradle on Eclipse Temurin), PHP (php-fpm or Apache with Composer), Ruby (Bundler/Puma), Rust (Cargo) and static sites on nginx or nginx-unprivileged.
What the generated Dockerfile does, stage by stage
Using the Node.js template as the example:
- build — starts from
node:22-alpine, copiespackage.jsonand the lock file, runsnpm ciwith a cache mount, copies the source and runsnpm run build. - deps — installs production dependencies only (
npm ci --omit=dev), so test runners and bundlers never reach the final image. - runtime — a clean base image receives
node_modulesfrom deps anddistfrom build, setsNODE_ENV=production, switches to the built-innodeuser, exposes the port, declares a HEALTHCHECK and starts the server with an exec-formCMDso signals reach the process.
Tips before you build
- Use the exec form (
CMD ["node", "dist/server.js"]) that the generator writes; the shell form wraps the process in/bin/sh, which swallowsSIGTERMand makesdocker stopwait ten seconds. - Pin base image tags (
3.12-slim, notlatest) and rebuild regularly to pick up security patches. - Pass secrets at run time with
--env-fileor your orchestrator, never withENVin the Dockerfile — anyone with the image can read it. - For Go and Rust, the multi-stage option is always on: the compiler image is hundreds of megabytes while the binary is a few.
- Front the container with the nginx config generator for TLS and caching, or combine it with a database and cache using the Docker Compose generator.
Image size reference
| Base image | Approximate size | Notes |
|---|---|---|
node:22-alpine | ~55 MB | musl libc; native modules may need rebuilding |
node:22-slim | ~75 MB | Debian; safest for native addons |
python:3.12-slim | ~50 MB | Preferred over Alpine for packages with C extensions |
eclipse-temurin:21-jre-alpine | ~90 MB | JRE only; the JDK stays in the build stage |
gcr.io/distroless/static-debian12 | ~2 MB | No shell — great for Go/Rust, but no HEALTHCHECK via curl |
nginxinc/nginx-unprivileged:alpine | ~20 MB | Listens on 8080 and runs as uid 101 |
Dockerfile Generator FAQ
Which Dockerfile generator option matters most for image size?
Multi-stage builds. Compilers, dev dependencies and build caches stay in the first stage, so a Node app typically drops from 1 GB to under 150 MB and a Go service to a few megabytes.
Why does the Dockerfile copy package.json before the rest of the code?
Docker caches each layer. If only your source changes, the dependency install layer is reused and the build takes seconds instead of minutes. Copying everything first would invalidate that cache on every change.
Do I need BuildKit for the cache mounts?
Yes, but BuildKit has been the default builder since Docker 23 (2023) and the # syntax=docker/dockerfile:1 line enables the feature explicitly. Untick the option if you build with an old daemon or a tool that does not support mounts.
How do I pass environment variables at run time?
Keep non-secret defaults in the ENV block and provide the rest with docker run --env-file .env or in your compose file. Convert between formats with the .env converter.
Why is the HEALTHCHECK written with node or python instead of curl?
Slim and Alpine images often do not include curl, and installing it adds size and attack surface. The runtime that is already in the image can make the HTTP probe.
Can I generate a Dockerfile for Next.js, Django or Spring Boot?
Yes — they are the Node, Python and Java templates respectively. Adjust the start command (for example node .next/standalone/server.js, gunicorn project.wsgi) and the health path if your framework uses a different one.