# gaphor/gaphor

Gaphor is the simple modeling tool

Repository: https://github.com/gaphor/gaphor
Canonical: https://ross.abutalabs.com/products/gaphor
Homepage: https://gaphor.org
Language: Python
License Family: other
Topics: python, uml, modeling, gnome, gtk, diagram, sysml, mbse, model-based-systems-engineering, c4model, fta, stpa
Last push: 2026-08-26T05:39:46+00:00

## Health v2 (maintenance only)
Score: 85/100 (v2, computed 2026-09-03T02:20:16.233290+00:00)
- activity 99, release rhythm 58, longevity 100
- inputs: {"age_days": 6279, "days_push": 7, "days_rel": 123, "gap_med": 112.0, "n_releases_24m": 7}
- flags: no_license
- formula: round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10)

## Adoption (not part of the score)
Stars 2265, forks 240 (observed 2026-08-28T04:06:32.655999+00:00)

## What it is
Gaphor is an open-source UML and SysML modeling application written in Python with GTK. It implements a fully-compliant UML 2 data model and supports SysML, RAAML, and C4 modeling, going beyond simple diagram drawing.

## Use cases
- draw UML class diagrams
- create SysML block definition diagrams for systems engineering
- model software architecture with the C4 model
- document application design with diagrams
- build state machine and interaction diagrams
- model-based systems engineering (MBSE) modeling
- export diagrams for documentation

## When to choose
- you need a free, open-source, cross-platform UML/SysML modeling tool
- you want a real UML 2 data model rather than just drawing shapes
- you do model-based systems engineering and need SysML or RAAML support
- you want an easy-to-use modeler that works for beginners and experts

## When to avoid
- you need collaborative, cloud-based diagramming like Lucidchart or draw.io integrations
- you need round-trip code generation for a specific language out of the box
- you only need quick whiteboard-style sketches without a formal model

## Facets
- artifact type: application
- maturity: active
- function: gui, documentation, graphics, developer-tools
- domain: developer-tools, desktop-applications, simulation
- platform: windows, python, cross-platform
- tags: uml, sysml, c4-model, mbse, diagramming, gtk, raaml, model-based-systems-engineering, software-architecture, linux, macos, desktop

## Member repositories
- gaphor/gaphor (main) score 85

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:06:32.655999+00:00.
- Health v2: computed from the inputs above; adoption is never an input.
- Inferred fields (summary, facets, guidance): AI-extracted, prompt v1, taxonomy v1, on 2026-08-30T02:42:24.573981+00:00, confidence not recorded.
  - readme: https://github.com/gaphor/gaphor (fetched 2026-08-28T04:06:32.655999+00:00, sha 0a52e856e46e)
  - homepage: https://gaphor.org (fetched 2026-08-29T10:23:12.413530+00:00, sha a636f3df82ee)
  - registry_pypi: https://pypi.org/pypi/gaphor/json (fetched 2026-08-29T10:23:12.424570+00:00, sha 1ee09392effd)
- Data as of 2026-08-30T08:39:29.467469+00:00.