CLI Reference

Complete reference documentation for all Railpack CLI commands.

Common Options

The following options are available across multiple commands:

Flag	Description
--env	Environment variables to set. Format: KEY=VALUE
--previous	Versions of packages used for previous builds. These versions will be used instead of the defaults. Format: NAME@VERSION
--build-cmd	Build command to use
--start-cmd	Start command to use
--config-file	Path to config file to use
--error-missing-start	Error if no start command is found

Commands

build

Builds a container image from a project directory using BuildKit.

Usage:

railpack build [options] DIRECTORY

Options:

Flag	Description	Default
--name	Name of the image to build
--output	Output the final filesystem to a local directory
--platform	Platform to build for (e.g. linux/amd64, linux/arm64)
--progress	BuildKit progress output mode (auto, plain, tty)	auto
--show-plan	Show the build plan before building	false
--cache-key	Unique id to prefix to cache keys

prepare

Generates build configuration files without performing the actual build. This is useful for platforms that want to:

• Build with a custom frontend and need to save the build plan to a railpack-plan.json file
• Log the Railpack pretty output to stdout
• Save the additional build information for later use

Usage:

railpack prepare [options] DIRECTORY

Options:

Flag	Description
--plan-out	Output file for the JSON serialized build plan
--info-out	Output file for the JSON serialized build result info

plan

Analyzes a directory and outputs the build plan that would be used.

Usage:

railpack plan [options] DIRECTORY

Options:

Flag	Description
--out, -o	Output file name for the plan

info

Provides detailed information about a project’s detected configuration, dependencies, and build requirements.

Usage:

railpack info [options] DIRECTORY

Options:

Flag	Description	Default
--format	Output format (pretty, json)	pretty
--out	Output file name

schema

Outputs the JSON schema for Railpack configuration files, used by IDEs for autocompletion and validation.

Usage:

railpack schema

frontend

Starts the BuildKit GRPC frontend server for internal build system use.

Usage:

railpack frontend

Global Options

These options can be used with any command:

Flag	Description
--help, -h	Show help information
--version, -v	Show version information
--verbose	Enable verbose logging