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Design a database schema visually, without leaving your IDE. Diagrams are plain .erd.json files in your project, and the editor never connects to a database.

Getting started

• Create an empty file with a .erd.json extension and open it. It opens in ERD Editor. • Right-click the canvas for every action: add a table, or choose Import to start from a .sql, GraphQL, DBML or AML file.

• Edits are written to the file a fraction of a second after you stop. Undo and redo, on the editor's toolbar, are its own history.

Features

• Design — tables, columns, memos and table groups, four relationship cardinalities, ON DELETE and ON UPDATE, alternate keys, Auto Layout

• Import — SQL DDL, GraphQL SDL, DBML and AML, replacing the diagram or adding to it • Export — DDL for eight databases, code in 22 languages and ORMs, PNG and SVG • Navigate — a command palette, an Explorer tree with find and replace, Graph and Flow views • History — undo and redo, time travel through the session, a diff viewer against another file • 25 languages and a System, Light or Dark theme, following the IDE by default • Coding agents — Claude Code or Codex edits the diagram live on the canvas (Coding agents, below)

• Multiple editors — the same diagram open in several editors, such as a split, stays in sync

Databases: Databricks, MariaDB, MSSQL, MySQL, Oracle, PostgreSQL, Snowflake, SQLite

Code: TypeScript, GraphQL, C#, Java, JPA, Kotlin, Scala, Go, SQLAlchemy, TypeORM, Sequelize, Drizzle, DBML, AML, Mermaid, PHP, Doctrine, Rust, SeaORM, Swift, Zod, JSON Schema

Every feature step by step: the Editing Guide.

Coding agents

A coding agent such as Claude Code or Codex edits the diagrams of the projects open in this IDE through the ERD Editor MCP server. Each change shows up on the canvas as it happens, and the agent's undo reverts only its own edits.

Add it with one command, in your project folder (Node.js 22.12 or later):

Claude Code

claude mcp add --transport stdio erd-editor -- npx -y @dineug/erd-editor-mcp

Codex

codex mcp add erd-editor -- npx -y @dineug/erd-editor-mcp

Then trust the project, start the agent in the same folder and ask, for example "Add a reviews table to schema.erd.json, related to users and products". Other clients and the tool list are in the MCP server's README.

Unticking Settings | Tools | ERD Editor → Coding agents turns the connection off for the whole IDE, as an untrusted project does for itself: the agent can then read the diagrams but never writes them. In an IDE installed as a Flatpak, which the MCP server cannot reach, the agent edits the files on disk, so close the diagram first: ERD Editor does not reload a file changed on disk.

Settings

Settings | Tools | ERD Editor holds, for the whole IDE, the appearance, gray color and accent color, the display language and Coding agents. Auto, the default, follows the IDE's theme and language, and the editor's theme builder and language button change these same settings.

Requirements

• An IntelliJ-based IDE, 2025.2 or later, running on the JetBrains Runtime, since the editor is a JCEF webview.

Documentation

• Editing Guide — every editor feature • MCP — the MCP server and its tools • Documentation

Also available

• Web app — installable PWA with real-time collaboration • Google Drive app — open and save diagrams in Google Drive

• VS Code extension • Obsidian plugin • @dineug/erd-editor — the editor as a custom element for your own app

• @dineug/erd-editor-mcp — the MCP server coding agents edit diagrams through