Loading page
About this tool
Describe your runtime, dependencies and start command to get a precise, copy-ready AI prompt for a production Dockerfile.
The Dockerfile Prompt Builder turns a plain description of your runtime, dependencies, port and start command into a precise AI prompt for generating a production-ready Dockerfile. It encodes Docker's published best practices — pinned base-image tags, dependency-first layer caching, multi-stage builds and a non-root user — so the assistant you paste it into cannot skip the hardening steps. It is built for developers who want a correct container build on the first generation instead of after five rounds of correction.
Open Dockerfile Prompt Builder on AltFTool — it loads instantly in your browser.
Upload or drag in the file you want to work with.
Adjust the settings and preview the result.
Download the finished file to your device.
Every prompt can demand pinned tags, layer caching, multi-stage builds, non-root users and a .dockerignore.
Eight presets (Node, Python, Go, Java, Ruby, Rust, PHP, .NET) pre-fill the current LTS base image and install commands.
The prompt explicitly instructs the model to use only the packages and commands you listed.
State the runtime and version, the exact dependency manifest to copy first, the install/build/start commands, the port, and the hardening you require (multi-stage, non-root, pinned tags). This tool assembles all of that into one structured prompt; vague prompts like 'write a Dockerfile for my app' are what produce bloated single-stage images running as root.
A multi-stage build keeps compilers, package managers and build caches out of the final image, which makes it smaller and reduces the attack surface. For compiled languages the difference is dramatic — a Go builder image is over 800 MB while a distroless final stage with the binary is typically under 30 MB.
Docker caches each layer, so if you copy package-lock.json (or requirements.txt, go.sum, etc.) and install dependencies before copying your source, the slow install layer is reused on every rebuild where only code changed. Copying everything in one step invalidates the cache and reruns the full install on every build.
Yes — Docker's own best-practice documentation recommends creating a dedicated user and switching to it with the USER instruction, because a process that escapes a root container has root-equivalent leverage on shared resources. The generated prompt includes this as a hard requirement when you tick 'Run as non-root user'.