Entity Relationship Diagram Designer (ERD Designer) is a tool for visually designing database Entity Relationship Diagrams (ER diagrams).
Open and edit files directly on Google Drive™, and export your design as DDL, table specifications, or images.


■ Design on a Canvas

Place tables with drag-and-drop and define relationships by connecting them — foreign keys are synchronized automatically.
The canvas is boundless, and the search panel (Ctrl+F / Cmd+F) finds tables, columns, relations, and memos at once, so large schemas stay manageable.
With Perspectives, group tables and memos by feature or purpose and switch between views.


■ Seven Major Databases

Generate DDL for PostgreSQL, MySQL, MariaDB, MS SQL Server, SQLite, BigQuery, and Snowflake, each following its own dialect.
Schemas (datasets in BigQuery), indexes, CHECK constraints, CHARACTER SET / COLLATE, and BigQuery STRUCT types
are supported according to what each database offers. The database type is chosen when you create the diagram.


■ Output Your Team Can Use

- DDL (CREATE TABLE scripts)
- Table specifications — created as a Google Sheets™ spreadsheet in your My Drive
- Diagram output — PNG, interactive SVG, or interactive HTML
  SVG and HTML open in any browser and support pan/zoom and perspective switching


■ AI Agent Integration (Experimental)

A plugin lets coding agents such as Claude Code edit .erd files directly.
It targets a local path synced by Google Drive™ for desktop, and enabling "Sync Google Drive™" brings the agent's edits into your canvas.
(This is an experimental feature, and its behavior may change.)


■ Define a Column Once, Reuse It Everywhere

Define a column once to reuse it across multiple tables — changing the type definition propagates to every place it's used.
You can also bundle common columns such as created_at / updated_at into a group and apply them to a table in one step.


■ Working Together on Google Drive™

Files are stored on Google Drive™ and can be opened by your teammates according to your sharing settings.
Simultaneous editing is not supported (optimistic concurrency control — you are notified on a conflict and can reload the latest content).
Enabling "Sync Google Drive™" from the gear menu detects changes made by others or by external tools
about every 10 seconds and brings them into the canvas as an undoable edit.
This setting is saved per diagram (default: off).


■ Import Existing Work (Experimental)

- DDL import — paste the DDL of an existing database to generate an ER diagram
- ERMaster .erm files — a .erd file is created in the same folder, ready to edit


■ What This App Accesses

This app reads and writes only the files opened with it and the files it creates.
It never browses the rest of your Google Drive™.


【SUPPORTED DATABASES】
PostgreSQL, MySQL, MariaDB, MS SQL Server, SQLite, BigQuery, Snowflake


* The same .erd file can also be edited in the browser version and the VSCode extension.
  Because .erd is plain JSON, you can manage it in Git and read the diff in a pull request.


This application is published as OSS at https://github.com/kajitiluna/erd-designer

Features are added continuously. See the changelog at https://github.com/kajitiluna/erd-designer/blob/main/CHANGELOG.md for the latest updates.
For detailed documentation, please visit https://github.com/kajitiluna/erd-designer/wiki


Google Drive™ and Google Sheets™ are trademarks of Google LLC.