Gaphor

Free plan LinuxMacWindows

What Gaphor is

Gaphor is a free desktop modeling application for visualizing and documenting applications and systems with UML, SysML, RAAML, and C4. It implements a UML 2 data model and the UML, SysML, and RAAML OMG standards, and supports C4. Diagram choices include Class, Interaction, State Machine, Block Definition, and Requirements; users can mix diagram items and apply custom styling through the built-in engine. Diagrams export as SVG, PNG, PDF, or EPS, and models can be batch-exported. Gaphor can also produce a self-contained, static, interactive, read-only HTML report that can be viewed without a server or backend. As a Python library, it can inspect, generate, or update models through scripts or Jupyter notebooks. A Sphinx extension embeds diagrams in reStructuredText or Markdown documentation. Gaphor is open source under the Apache 2 license and runs on Windows, macOS, and Linux. Windows options include an installer, portable version, or Winget; macOS 10.15 or newer is required. Linux options include Flatpak, Arch, and Debian/Ubuntu packages.

Who it suits

Gaphor suits people who need to model applications or systems using UML, SysML, RAAML, or C4. Its scripting, reporting, and Sphinx support also suit users incorporating models into documentation workflows.

What it does well

Supports UML, SysML, RAAML, and C4
Exports diagrams to SVG, PNG, PDF, or EPS
Generates standalone interactive HTML model reports
Usable as a Python library with Jupyter notebooks
Available on Windows, macOS, and Linux

What to know first

macOS 10.15 or newer is required
Community contact and issue reporting are through Matrix and GitHub

Plans

Plan	Billed and limits	Price
Gaphor	100% open source · Apache 2 license	Free

As gaphor.org lists them, read 29 Sept 2026. The maker's own page has the final word.

Getting started

Choose the download route for Windows, macOS, or Linux.
On Windows, download the installer or portable version, or install with Winget.
On macOS 10.15 or newer, choose the ARM or Intel installer.
On Linux, use Flatpak or choose an Arch or Debian/Ubuntu package.
Open Gaphor and create or work with a model; use the GUI or CLI to access extensions.

Verdict

Gaphor combines standards-based modeling with diagram exports, HTML reports, and Python scripting. It is free and cross-platform, with macOS 10.15 or newer required.

Questions

How much does Gaphor cost?

The Gaphor plan costs nothing. The application is open source under the Apache 2 license.

Which platforms does Gaphor support?

Gaphor is available for Windows, macOS, and Linux. macOS 10.15 or newer is required.

Is Gaphor open source?

Yes. Gaphor is open source under the Apache 2 license.

What modeling standards does Gaphor support?

It supports UML, SysML, RAAML, and C4, and implements a UML 2 data model as well as the UML, SysML, and RAAML OMG standards.

What export formats are available?

Diagrams can be exported as SVG, PNG, PDF, or EPS. Gaphor can also batch-export every diagram in a model.

How can users get community support?

The project offers community contact through Matrix chat and accepts issue reports through GitHub.

Facts from Gaphor's own pages

Diagram types: It supports diagrams including Class, Interaction, State Machine, Block Definition, and Requirements diagrams, and lets users mix diagram items. · gaphor.org, 29 Sept 2026
Documentation integration: Gaphor provides a Sphinx extension for embedding its diagrams in reStructuredText or Markdown documentation. · docs.gaphor.org, 29 Sept 2026
Export: Gaphor exports diagrams as SVG, PNG, PDF, or EPS and can batch-export every diagram in a model. · docs.gaphor.org, 29 Sept 2026
Extensibility: Gaphor can be extended with plugins and users can access their own extensions through the GUI or CLI. · gaphor.org, 29 Sept 2026
HTML reports: It can generate a self-contained, static, interactive, read-only HTML report of a model that requires no server or backend to view. · docs.gaphor.org, 29 Sept 2026
Linux distribution: The download page recommends Flatpak for Linux and also lists Arch and Debian/Ubuntu packages. · gaphor.org, 29 Sept 2026
macOS requirement: The download page says Gaphor requires macOS 10.15 or newer and provides ARM and Intel installers. · gaphor.org, 29 Sept 2026
Modeling standards: Gaphor implements a fully compliant UML 2 data model and the UML, SysML, and RAAML OMG standards, and supports the C4 model. · gaphor.org, 29 Sept 2026
Model styling: Users can customize diagrams with a built-in styling engine. · gaphor.org, 29 Sept 2026
Purpose: Gaphor is a modeling application for UML, SysML, RAAML, and C4 used to visualize and document applications and systems. · gaphor.org, 29 Sept 2026
Scripting: Gaphor can be used as a Python library with scripts or Jupyter notebooks to inspect, generate, or update models. · docs.gaphor.org, 29 Sept 2026
Support: The project provides community contact through Matrix chat and accepts issue reports through GitHub. · gaphor.org, 29 Sept 2026
Windows distribution: Windows users can download an installer or portable version, or install Gaphor with Winget. · gaphor.org, 29 Sept 2026

Where Gaphor stands on Freedom251

UML Modeling Software#8 of 26