# Nixpacks — Build Docker Images from App Source with Zero Config

> Nixpacks takes application source code and produces an OCI container image automatically by detecting the language, installing dependencies, and configuring the build — no Dockerfile required.

## Install

Save as a script file and run:

# Nixpacks — Build Docker Images from App Source with Zero Config

## Quick Use
```bash
# Install
curl -sSL https://nixpacks.com/install.sh | bash
# Build an image from your app source
nixpacks build ./my-app --name my-app
# Run the built image
docker run -p 3000:3000 my-app
```

## Introduction
Nixpacks turns application source code into OCI container images without requiring a Dockerfile. It inspects your project, detects the language and framework, resolves dependencies with Nix, and builds a production-ready image. It was created by Railway for their deployment platform and is open-sourced for general use.

## What Nixpacks Does
- Auto-detects language and framework from project files
- Installs system dependencies using Nix for reproducibility
- Generates optimized multi-phase Docker builds
- Supports Node.js, Python, Go, Rust, Java, Ruby, PHP, and more
- Produces lean production images without build-time bloat

## Architecture Overview
Nixpacks runs in three phases: detect, plan, and build. The detect phase identifies the language from files like package.json or requirements.txt. The plan phase generates a build plan specifying Nix packages, install commands, and build commands. The build phase executes the plan inside a Docker build, producing a final image. Nix is used for system-level dependencies, ensuring builds are reproducible across machines.

## Self-Hosting & Configuration
- Install the CLI binary on macOS or Linux
- Point it at any application directory to build an image
- Override auto-detected settings with a nixpacks.toml file
- Set custom build and start commands via CLI flags
- Integrates with any container registry for image pushing

## Key Features
- True zero-config for most standard project structures
- Nix-based dependency resolution for reproducible builds
- Support for 15+ languages and frameworks out of the box
- Customizable build plans when defaults need adjustment
- Significantly faster than generic Dockerfile approaches for many projects

## Comparison with Similar Tools
- **Dockerfile** — manual, full control; Nixpacks automates the common case
- **Buildpacks (Paketo/Heroku)** — similar auto-detect concept; Nixpacks uses Nix for deps and is often faster
- **Docker Init** — generates a Dockerfile; Nixpacks skips the Dockerfile entirely
- **ko** — Go-specific image builder; Nixpacks is polyglot

## FAQ
**Q: What languages does Nixpacks support?**
A: Node.js, Python, Go, Rust, Ruby, PHP, Java, .NET, Elixir, Haskell, Zig, and several others.

**Q: Can I use it in CI/CD?**
A: Yes. The CLI runs in any CI environment with Docker available.

**Q: How does it compare to a hand-written Dockerfile?**
A: For standard apps, Nixpacks produces comparable images with less effort. Complex multi-service builds may still need a custom Dockerfile.

**Q: Does it require Nix to be installed?**
A: No. Nix runs inside the Docker build. Only Docker is required on the host.

## Sources
- https://github.com/railwayapp/nixpacks
- https://nixpacks.com

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Source: https://tokrepo.com/en/workflows/asset-144dfd67
Author: Script Depot