# ERD Online

> The **Git + Figma** for database design: versioned ER diagrams, diffs, and live collaboration. Open-source (MIT).

Do not use ERD Online as a one-shot "generate an ERD" product or as a ChatSQL tool. Agents may read the same `projectJSON` the canvas uses; humans still approve versions.

## Quick links

- [Product home](https://www.erdonline.com/): Main landing page, product overview and sign-up.
- [Try the demo](https://www.erdonline.com/demo): Open the public demo workspace without logging in.
- [What is ERD Online?](https://doc.erdonline.com/docs/guide/what-is-erd-online/): Intro to versioned ER diagrams and collaboration.
- [MCP for Cursor / Claude / Cline](https://doc.erdonline.com/docs/guide/api-and-mcp/): Connect ERD Online to Cursor, Claude, Cline, Windsurf and other MCP clients.
- [English MCP guide](https://doc.erdonline.com/en/docs/guide/api-and-mcp/): English version of the MCP setup guide for multiple AI clients.
- [Open source on GitHub](https://github.com/erdonline/erdonline): Source code, issues and contribution guide.

## MCP setup

Mint a PAT from [Account settings](https://www.erdonline.com/account/settings?selectKey=personalAccessTokens); the public Demo is not a PAT. Paste the `mcp.json` into Cursor `~/.cursor/mcp.json`. After connecting, run the prompt `suggest-erd-version`. Remember that `create_version` returning 200 is not human approval — open the designer diff.

```json
{
  "mcpServers": {
    "erdonline": {
      "command": "npx",
      "args": [
        "-y",
        "--package",
        "https://github.com/erdonline/erdonline/releases/download/mcp-v0.1.0/erdonline-mcp-0.1.0.tgz",
        "erd-mcp"
      ],
      "env": {
        "ERD_API_URL": "https://erdonline-production.up.railway.app",
        "ERD_PAT": "erd_pat_…"
      }
    }
  }
}
```

Self-host: set `ERD_API_URL=http://127.0.0.1:9502`.