# Copier — Render Project Templates with Answers and Updates

> Copier is a Python-based project scaffolding tool that renders templates from Git repositories, supports answer-driven customization, and can update previously generated projects when the template evolves.

## Install

Save in your project root:

# Copier — Render Project Templates with Answers and Updates

## Quick Use
```bash
pipx install copier
copier copy gh:user/my-template ./my-project
```

## Introduction
Copier is a command-line tool and Python library for generating projects from template repositories. It asks the user a series of questions, renders Jinja templates with the answers, and can later update generated projects when the upstream template changes — preserving local modifications.

## What Copier Does
- Generates project scaffolds from Git-hosted or local template directories
- Prompts users with configurable questions and validates answers with types and constraints
- Renders files and directory names using Jinja2 templating with the collected answers
- Updates previously generated projects by replaying template changes on top of local edits
- Supports conditional file inclusion, multi-choice prompts, and computed values

## Architecture Overview
Copier clones the template repository, reads a `copier.yml` configuration file that defines questions and settings, collects answers interactively or from a file, and renders all Jinja2 templates in the source tree into the destination directory. A `.copier-answers.yml` file is saved in the generated project, enabling future `copier update` runs to diff the old template version against the new one and apply changes while respecting local modifications via a three-way merge.

## Self-Hosting & Configuration
- Install via pipx: `pipx install copier` (recommended) or pip: `pip install copier`
- Define template questions and defaults in a `copier.yml` at the template root
- Use Jinja2 syntax in filenames and file contents with `{{ variable }}` placeholders
- Tag template versions with Git tags so consumers can update between specific releases
- Run `copier update` in a generated project to pull in upstream template improvements

## Key Features
- Template update workflow that three-way-merges upstream changes with local project edits
- Rich question types including text, integer, float, boolean, choice, and multi-choice
- Conditional file rendering and directory creation based on answer values
- Subdirectory support for templates that live inside a larger monorepo
- Extensible via pre- and post-generation tasks defined in the template configuration

## Comparison with Similar Tools
- **Cookiecutter** — The original Python project templater; Copier adds template updates, richer question types, and Git-tag versioning
- **Yeoman** — Node.js generator ecosystem; Copier is Python-native with built-in update support
- **degit** — Copies Git repos without history; Copier adds templating, questions, and updates
- **Hygen** — File generator for JavaScript projects; Copier is language-agnostic with answer-driven scaffolding
- **Plop** — Micro-generator for adding files to existing projects; Copier generates full project scaffolds with lifecycle updates

## FAQ
**Q: How does Copier handle template updates?**
A: Copier stores your answers in `.copier-answers.yml`. Running `copier update` diffs the old and new template versions, then applies the changes to your project with a three-way merge.

**Q: Can I use Copier with non-Python projects?**
A: Yes. Copier is language-agnostic. Templates can generate projects in any language or framework.

**Q: Does Copier support private Git repositories?**
A: Yes. Copier uses Git for cloning, so any repository accessible via SSH keys or credential helpers works.

**Q: How do I skip certain questions programmatically?**
A: Define `when` conditions in `copier.yml` that reference previous answers. Questions with a false `when` are skipped and use their default values.

## Sources
- https://github.com/copier-org/copier
- https://copier.readthedocs.io/

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Source: https://tokrepo.com/en/workflows/asset-bd98bba9
Author: AI Open Source