orm2erd

You already built the app — your ORM models are the schema. orm2erd reads them and generates an ERD (Entity-Relationship Diagram) for you, instead of you drawing and maintaining one by hand.

Status: early development — see the tables below for what's supported today vs. planned.

What it does

orm2erd scans your project, figures out which ORM you're using, and turns your existing models/schema into diagram code — Mermaid, DBML, PlantUML, D2, and more. No manual diagramming, no drift between your code and your docs.

detect ORM → resolve entry point(s) → parse/introspect → normalize to IR → emit diagram code(s) → write file(s)

Supported ORMs

| | ORM | Status | | --- | --- | --- | | | Prisma | ✅ Supported | | | Sequelize | ✅ Supported | | | TypeORM | 🚧 Planned | | | Drizzle | 🚧 Planned |

Output formats

| | Format | Status | | --- | --- | --- | | | Mermaid | ✅ Supported | | | DBML | ✅ Supported | | | PlantUML | 🚧 Planned | | | D2 | 🚧 Planned |

Installation

Run without installing (recommended — always gets the latest version):

npx orm2erd

Or install globally:

npm i -g orm2erd
orm2erd

Usage

Interactive:

npx orm2erd

┌  orm2erd
│
◇  Detected: prisma
◆  Entry point for prisma:
│  prisma/schema.prisma
◆  Output format(s):
│  mermaid
◆  Output path:
│  erd.mermaid
◆  Type labels:
│  Canonical
│
◇  Written to erd.mermaid
│
└  Done

Non-interactive (CI-friendly):

npx orm2erd --orm prisma --entry ./prisma/schema.prisma --format mermaid,dbml --out ./erd

You can select multiple output formats in a single run — the schema is parsed once and reused across every format you pick. --out accepts either a bare name (erd, gets each format's extension appended) or a full filename (erd.md, used exactly as given when there's only one output format).

By default, field types are emitted in a canonical, portable form (e.g. string, int). Pass --type-mode native to emit the ORM's own type names instead (e.g. Prisma's String, Int):

npx orm2erd --orm prisma --entry ./prisma/schema.prisma --format mermaid --type-mode native

Why

Diagrams drawn by hand go stale the moment the schema changes. Your ORM already has an accurate, structured picture of your data model — orm2erd just reads that instead of asking you to redraw it.

Contributing

See CLAUDE.md for architecture, the adapter/emitter contract, and design decisions.

License

MIT