BYTETOOLS

Dockerfile Generator

Generate a production-ready Dockerfile and matching .dockerignore for Node, Python, Go, PHP, Java or static sites, with multi-stage builds and a non-root user.

Dockerfile

# syntax=docker/dockerfile:1

# ---- Build stage -------------------------------------------------------
FROM node:22-alpine AS builder
WORKDIR /app

# Copy manifests first so this layer is cached until dependencies change.
COPY package*.json ./
RUN npm ci

COPY . .
RUN npm run build

# ---- Runtime stage -----------------------------------------------------
FROM node:22-alpine
WORKDIR /app

COPY --from=builder /app/node_modules /app/
COPY --from=builder /app/dist /app/
COPY --from=builder /app/package.json /app/

ENV NODE_ENV=production

# node already exists in this base image.
RUN chown -R node:node /app
USER node

EXPOSE 3000

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

.dockerignore

# Generated by ByteTools
.git
.gitignore
.dockerignore
Dockerfile
*.md
.env
.env.*
.vscode
.idea
node_modules
npm-debug.log
dist
.next

Review the copied build artefacts before shipping — every project lays out its output directory differently, so the COPY --from=builder paths are a starting point rather than a guarantee.

What is the Dockerfile Generator?

The ByteTools Dockerfile Generator turns a short form into a Dockerfile you can commit straight away.

  • Six stacks with sensible base images and install commands preconfigured
  • Optional multi-stage build with COPY --from=builder into a slim runtime
  • Non-root USER handling that reuses the base image's existing user where one exists
  • Layer-cache friendly ordering: manifests copied and installed before the source
  • Optional HEALTHCHECK block and ENTRYPOINT/CMD switch
  • Generates a matching .dockerignore and runs entirely in your browser

How to use the Dockerfile Generator

  1. 1

    Choose your stack: Node.js, Python, Go, PHP, Java or a static site served by nginx.

  2. 2

    Adjust the base image, working directory, exposed port and start command, or leave them blank to use the stack defaults.

  3. 3

    Add any environment variables as KEY=value lines, one per line.

  4. 4

    Toggle multi-stage build, non-root USER, HEALTHCHECK and ENTRYPOINT to match how you deploy.

  5. 5

    Copy or download both the Dockerfile and the generated .dockerignore.

About the Dockerfile Generator

The ByteTools Dockerfile Generator turns a short form into a Dockerfile you can commit straight away. Pick your stack, adjust the base image, working directory, exposed port and start command, and the file is rebuilt as you type — including a matching .dockerignore so your build context stays small.

The defaults follow the practices that actually matter in production: dependency manifests are copied before the rest of the source so Docker can cache the install layer, a multi-stage build keeps compilers and dev dependencies out of the final image, and the container drops to a non-root user before it runs.

Everything is assembled in your browser from string templates, so nothing is uploaded, no image is ever pulled and no build is executed. You get plain text you can read line by line, edit to match your project's real output paths, and check into version control alongside the code it builds.

Frequently asked questions

What should a production Dockerfile include?

A pinned base image, dependency manifests copied and installed before the rest of the source so the layer caches, a non-root user, an explicit EXPOSE, and an exec-form CMD. A multi-stage build is worth adding whenever your project has a compile or bundle step, because it keeps build tooling out of the shipped image.

Why use a multi-stage Docker build?

The build stage can hold compilers, dev dependencies and source code, while the runtime stage copies only the finished artefacts. That usually cuts image size dramatically and shrinks the attack surface, since none of the build tooling ships to production.

Why should a container not run as root?

If an attacker escapes your application process, running as root inside the container gives them far more room to move, especially when volumes are mounted from the host. Creating a dedicated user and switching to it with USER is a one-line change that removes that whole class of risk.

What is a .dockerignore file for?

It keeps files out of the build context that Docker sends to the daemon. Excluding .git, node_modules and local env files makes builds faster and stops secrets or huge folders being copied into an image by an accidental COPY . . instruction.

Do I need to change the COPY --from=builder paths?

Very likely, yes. Every project lays out its build output differently, so treat the copied artefact paths as a starting point and point them at wherever your build actually writes its output.

Is my configuration uploaded anywhere?

No. The Dockerfile is assembled from templates entirely inside your browser tab, so nothing you type — including environment variable names — ever leaves your machine.

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