Start here
Answer one question first: what do you want to get done today?
ERD Online is an open-source (MIT) database modeler: meaningful schema changes can be versioned with field-level diffs, and you can self-host. No install yet? Open the free Demo and look at a real diagram.
Try now: Open Demo (about 30 seconds to an example model)
Path 1: Feel the product (~5 minutes)
Best if you just discovered us.
- Positioning & boundaries → What is ERD Online
- Demo → copy to your project → change a column → Save version → open diff → Save a version and view the diff
You leave with your own version record—not just a screenshot.
Path 2: Bring an existing model in
Best if you already have dbdiagram / .dbml, or a live database.
| You have… | Open |
|---|---|
.dbml / dbdiagram export | Import DBML |
| MySQL / PostgreSQL / Oracle / SQL Server | Reverse engineer |
| Want a comparison vs other tools | Compare |
After import, save a version immediately as the baseline so later diffs mean something.
Path 3: Keep data on your side, or open APIs
Best if you need intranet deploy, approval, or agents/scripts on the same model.
| Goal | Open |
|---|---|
| Five-minute stack on your machine | Quick self-host |
| Full deploy & cloud topologies | Deployment |
| Roles & SQL approval | Roles and approval |
| Scripts / agents (API · MCP) | API and MCP |
| Let Cursor read the diagram, then suggest a version | Same guide; pick prompt suggest-erd-version. The public Demo is not a PAT. create_version API 200 is not human approval |
How to read these docs (30 seconds)
- User guides (this sidebar section): “how do I…” — you are here
- Self-host & open interfaces: deploy, data format, security
- Contribute & engineering (collapsed by default): for PR authors, not required to start
Long-form article index: Guide index