# What Are the Dependencies for Diagram Design? A Complete Guide to Installation and Requirements

> Discover diagram design dependencies. Learn about Python 3.9 requirements and optional Playwright for PNG export. Get your setup right for seamless diagram creation.

- Repository: [Cathryn Lavery/diagram-design](https://github.com/cathrynlavery/diagram-design)
- Tags: how-to-guide
- Published: 2026-08-20

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**Diagram Design requires only Python ≥3.9 and optionally Playwright for PNG export—all other functionality uses the Python standard library.**

Diagram Design is intentionally built as a lightweight, pure-Python project that minimizes external dependencies. According to the cathrynlavery/diagram-design source code, the repository relies almost entirely on built-in Python modules, making it easy to install and maintain across different environments. This guide covers exactly what you need to run each feature of the project.

## Core Dependencies: Python Standard Library Only

The foundation of Diagram Design requires **no third-party packages**. All core functionality—including type definitions, import tools, and validation—is implemented using only Python's built-in modules.

The following standard library modules power the main scripts:

- `argparse` – Command-line interface handling
- `json` – Configuration and data parsing
- `re` – Pattern matching for text extraction
- `pathlib` – Cross-platform file path operations
- `html` and `html.parser` – HTML processing and validation
- `urllib` – URL handling and network operations
- `base64`, `zlib`, `xml.etree.ElementTree` – Draw.io file parsing
- `dataclasses`, `collections` – Data structures and utilities

These modules are used across the entire codebase, from [`skills/diagram-design/scripts/drawio_extract.py`](https://github.com/cathrynlavery/diagram-design/blob/main/skills/diagram-design/scripts/drawio_extract.py) for Draw.io import to [`skills/diagram-design/scripts/self_check.py`](https://github.com/cathrynlavery/diagram-design/blob/main/skills/diagram-design/scripts/self_check.py) for built-in validation.

## Optional Dependency: Playwright for PNG Export

The **only external package** required for full functionality is Playwright. This dependency becomes necessary only when you need to export diagrams to PNG format.

As documented in the README's [Export to PNG / SVG](https://github.com/cathrynlavery/diagram-design/blob/main/README.md#export-to-png--svg) section, the `scripts/export-diagram` workflow uses Playwright to rasterize SVG output into PNG images.

### Installing Playwright for Diagram Design PNG Export

```bash

# Install the Playwright Python client

pip install playwright

# Download the required browser binaries (Chromium is used by Diagram Design)

playwright install chromium

```

Without Playwright installed, all other Diagram Design features continue to work normally. You can create, validate, and export SVG diagrams without any additional setup.

## Dependency Breakdown by Feature

| Feature | Required Packages | Source Location |
|:---|:---|:---|
| Core functionality and type definitions | Python ≥3.9 (standard library) | `skills/diagram-design/` (e.g., [`SKILL.md`](https://github.com/cathrynlavery/diagram-design/blob/main/SKILL.md), `references/*.md`) |
| Draw.io import and conversion | Python standard library (`base64`, `zlib`, `xml.etree.ElementTree`) | [`skills/diagram-design/scripts/drawio_extract.py`](https://github.com/cathrynlavery/diagram-design/blob/main/skills/diagram-design/scripts/drawio_extract.py) |
| Mermaid import and conversion | Python standard library (`json`, `re`, `dataclasses`) | [`skills/diagram-design/scripts/mermaid_extract.py`](https://github.com/cathrynlavery/diagram-design/blob/main/skills/diagram-design/scripts/mermaid_extract.py) |
| Self-check validation | Python standard library (`html.parser`, `collections`) | [`skills/diagram-design/scripts/self_check.py`](https://github.com/cathrynlavery/diagram-design/blob/main/skills/diagram-design/scripts/self_check.py) |
| CI verification suite (geometry, treemap, motion tests) | Python standard library | `scripts/verify-*.py` and `scripts/test-*.py` |
| **PNG export** | **Playwright** (`pip install playwright`) | `scripts/export-diagram` (documented in README) |
| Icon generation from static SVG assets | No additional packages | [`scripts/build-icons.py`](https://github.com/cathrynlavery/diagram-design/blob/main/scripts/build-icons.py) |

## Running Diagram Design Without External Dependencies

Most common use cases require zero package installation beyond Python itself. Here's how to validate a diagram file using only built-in modules:

```bash

# Run self-check validation—no pip install required

python3 skills/diagram-design/scripts/self_check.py path/to/diagram.html

# Expected output on success:

# OK

```

This script, located at [`skills/diagram-design/scripts/self_check.py`](https://github.com/cathrynlavery/diagram-design/blob/main/skills/diagram-design/scripts/self_check.py), demonstrates the project's commitment to standard-library-only implementations for core tooling.

## Key Files for Understanding Dependencies

| File | Purpose | Dependencies Used |
|:---|:---|:---|
| [`README.md`](https://github.com/cathrynlavery/diagram-design/blob/main/README.md) | Installation documentation | Documents Playwright requirement for export |
| [`skills/diagram-design/scripts/drawio_extract.py`](https://github.com/cathrynlavery/diagram-design/blob/main/skills/diagram-design/scripts/drawio_extract.py) | Draw.io import and conversion | `base64`, `zlib`, `xml.etree.ElementTree` |
| [`skills/diagram-design/scripts/mermaid_extract.py`](https://github.com/cathrynlavery/diagram-design/blob/main/skills/diagram-design/scripts/mermaid_extract.py) | Mermaid diagram extraction | `json`, `re`, `dataclasses` |
| [`skills/diagram-design/scripts/self_check.py`](https://github.com/cathrynlavery/diagram-design/blob/main/skills/diagram-design/scripts/self_check.py) | HTML validation and verification | `html.parser`, `collections` |
| `scripts/verify-*.py` and `scripts/test-*.py` | CI verification and testing | Various standard library modules |
| [`scripts/build-icons.py`](https://github.com/cathrynlavery/diagram-design/blob/main/scripts/build-icons.py) | Static icon generation from SVG assets | None (file I/O only) |

## Summary

- **Diagram Design dependencies are minimal by design**: Python ≥3.9 is the only hard requirement.
- **Playwright is the sole optional dependency**, needed exclusively for PNG export functionality via `scripts/export-diagram`.
- **All import tools** (Draw.io, Mermaid), **validation scripts**, and **CI verification** run on standard library modules.
- **No configuration files**, [`requirements.txt`](https://github.com/cathrynlavery/diagram-design/blob/main/requirements.txt), or [`pyproject.toml`](https://github.com/cathrynlavery/diagram-design/blob/main/pyproject.toml) dependency declarations are needed for core usage.

## Frequently Asked Questions

### Does Diagram Design require a requirements.txt file?

No. Because Diagram Design uses only Python's standard library for all core functionality, no [`requirements.txt`](https://github.com/cathrynlavery/diagram-design/blob/main/requirements.txt) or [`pyproject.toml`](https://github.com/cathrynlavery/diagram-design/blob/main/pyproject.toml) dependency declaration is necessary. You only need to install Playwright separately if you intend to export diagrams to PNG format.

### What Python version is required for Diagram Design?

Python 3.9 or newer is required. This ensures compatibility with modern type hint syntax and standard library features used throughout the codebase, particularly in [`skills/diagram-design/scripts/mermaid_extract.py`](https://github.com/cathrynlavery/diagram-design/blob/main/skills/diagram-design/scripts/mermaid_extract.py) which leverages `dataclasses` and other 3.9+ conventions.

### Can I use Diagram Design without installing Playwright?

Yes. Playwright is only required for PNG export. You can create diagrams, import from Draw.io and Mermaid formats, run validation with [`self_check.py`](https://github.com/cathrynlavery/diagram-design/blob/main/self_check.py), and export to SVG format without any external packages installed.

### Where is the Playwright dependency documented in the Diagram Design repository?

The Playwright requirement is documented in the [Export to PNG / SVG](https://github.com/cathrynlavery/diagram-design/blob/main/README.md#export-to-png--svg) section of the main [`README.md`](https://github.com/cathrynlavery/diagram-design/blob/main/README.md), which describes the installation steps and browser binary setup needed for rasterizing SVG output to PNG images.