# voormedia/rails-erd

Generate Entity-Relationship Diagrams for Rails applications

Repository: https://github.com/voormedia/rails-erd
Canonical: https://ross.abutalabs.com/products/rails-erd
Homepage: http://voormedia.github.io/rails-erd/
Language: Ruby
License: MIT
License Family: permissive
Last push: 2026-08-14T13:30:06+00:00

## Health v2 (maintenance only)
Score: 96/100 (v2, computed 2026-09-03T02:20:16.233290+00:00)
- activity 97, release rhythm 92, longevity 100
- inputs: {"age_days": 5827, "days_push": 19, "days_rel": 54, "gap_med": 3, "n_releases_24m": 4}
- flags: none
- formula: round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10)

## Adoption (not part of the score)
Stars 4105, forks 379 (observed 2026-08-28T04:08:35.640415+00:00)

## What it is
A Ruby gem that generates entity-relationship diagrams from Rails applications' Active Record models using reflection. It outputs Mermaid diagrams by default (rendering natively on GitHub) and can also produce styled PDF/PNG/SVG diagrams via Graphviz.

## Use cases
- generate ER diagrams for my Rails models
- document database schema relationships in a Rails app
- visualize Active Record associations including has_many :through
- create model diagrams that render on GitHub READMEs
- inspect a Rails app's domain model programmatically
- export database diagrams as PDF, PNG, or SVG

## When to choose
- you maintain a Ruby on Rails application and want automatic model documentation
- you need diagrams that capture meta-programmed associations via runtime reflection
- you want Mermaid output that renders natively on GitHub
- you need a customizable API to build your own model diagrams

## When to avoid
- your project is not built on Rails or Active Record
- you need diagrams for non-Ruby ORMs or raw SQL schemas
- you need a general-purpose diagramming tool unrelated to data models

## Facets
- artifact type: library
- maturity: stable
- function: documentation, data-visualization, developer-tools
- domain: web-development, developer-tools, documentation, databases
- platform: ruby, cli
- tags: rails, entity-relationship-diagram, active-record, mermaid, graphviz, erd

## Member repositories
- voormedia/rails-erd (main) score 96

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:08:35.640415+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 2026-08-29T18:23:14.935865+00:00, confidence not recorded.
  - readme: https://github.com/voormedia/rails-erd (fetched 2026-08-28T04:08:35.640415+00:00, sha 4a4b3fda4e87)
  - homepage: http://voormedia.github.io/rails-erd/ (fetched 2026-08-29T09:14:44.113739+00:00, sha 392913b174ad)
- Data as of 2026-08-30T08:39:29.467469+00:00.