ERD Editor

Entity-Relationship Diagram Editor for Obsidian

Design a database schema visually, right inside your vault. Diagrams are plain JSON files in your vault, next to your notes, so they sync, diff and back up like everything else in the vault.

The editor never connects to a database: it reads and writes your diagram files. You bring a schema in from a .sql dump or a GraphQL SDL, DBML or AML file, and take one back out as DDL or generated code.

Desktop only.

Installation

In Obsidian, open Settings → Community plugins, turn on community plugins if asked, choose Browse, search for ERD Editor (listing), then select Install and Enable.

To install by hand instead, download main.js, manifest.json and styles.css from the latest release into a folder named erd-editor under your vault's .obsidian/plugins, then turn on ERD Editor in Settings → Community plugins.

Getting started

Run ERD Editor: Create new diagram from Obsidian's command palette, or right-click a folder in the file explorer and choose New ERD. Either one creates an empty .erd file and opens it in the diagram view.

An empty diagram you can edit opens on the welcome screen, a menu of New Table, New Memo, Import, Command Palette and Shortcuts, which stays until its first table, shown memo or shown table group. Alt+N adds a table and Alt+Enter adds a column to it; Delete or Backspace removes the selection, and Alt+K toggles the primary key on the focused column.

To start from a schema you already have, right-click the canvas and choose Import, then Schema SQL for a .sql dump, GraphQL for a .graphql, .gql or .graphqls file, DBML for a .dbml file or AML for an .aml file; json opens an .erd.json file as it was saved, and takes no .erd file. Each one replaces the diagram in one undoable step, a schema's tables laid out by their relationships. Import and Add beside it takes the same five and adds the file to the diagram instead, its tables placed as new ones below everything already there, in one undoable step. The diagrams Create new diagram and New ERD make are .erd files, so to import or compare one, use a copy renamed to .erd.json.

Obsidian saves a diagram the way it saves a note: about two seconds after you stop editing, and when you close the tab or quit. Opening a file never rewrites it. Undo and redo are the diagram editor's own history.

Files

• .erd files show up in the file explorer and open in the diagram view.
• .erd.json files open in the diagram view from links. Obsidian reads their extension as json, so the file explorer and the quick switcher leave them out; turn on Settings → Files and links → Detect all file extensions and both list them and open them in the diagram view.
• A file the editor cannot read, such as one left with merge conflict markers or cut off by a sync, opens read-only and is left as it is rather than replaced by an empty diagram.

Features

Design

• Visual schema design — tables, columns, memos, and four relationship cardinalities (Zero One, Zero N, One Only, One N)
• Quick edits — Alt+N adds a table and Alt+Enter a column, Alt+K toggles the primary key on the focused column, or on every selected column when it is one of them, and Delete or Backspace removes the selection, each in one undo step; the Shortcuts page of the editor's Settings tab lists every key
• Link existing columns — while you draw a relationship with a mouse or a pen, the buttons beside the table it ends on either map the parent's key onto columns that table already has or add new ones, named after the parent table when the key is one word (user_id for user's id), and Map Columns in a relationship's right-click menu changes its columns later
• Referential actions — set On Delete and On Update (NO ACTION, CASCADE, SET NULL, SET DEFAULT, RESTRICT) from a relationship's right-click menu, which marks one the current database leaves out; the line shows them at its child end as D:C U:R, and View Option's Referential Actions hides the labels. SQL, DBML and AML import read them, and the DDL export and the code generators that have a place for them write the ones the target supports
• Alternate keys — View Option's Alternate Key marks the columns of each unique index over two or more columns as AK1.1, AK1.2, and SQL import reads a UNIQUE over several columns as one such index
• Table groups — draw a box behind related tables, which you name and can color, with New Table Group in the canvas menu or the editor's command palette, or group the selected tables from their right-click menu. A table joins a group when you drop it inside and leaves when you drop it outside, dragging a group by its title moves its tables with it, each member's header takes the group's color, View Option hides the groups, and DBML import and the Code Generator's DBML carry them as TableGroups
• Auto Layout — place every table again by Force, Flow or a vertical or horizontal tree from the canvas menu or the editor's command palette, table groups kept together, in one undo step; Force shows a preview you apply or cancel, and the others land at once
• Copy, paste and colors — copy tables and memos and paste them as new ones, into another diagram too or into a spreadsheet as a grid, hold Alt while dragging to duplicate them, and color a table, memo or table group from its right-click menu
• Clean diffs — the scroll position and zoom, the open tab, the code generator's language and name cases and the bracket type are locked by default, so the file keeps the values they had when locked and looking around never changes it; the file, written in a fixed order, also leaves out measured widths, connector anchors and removed items (see Keeping diffs clean)

Import

• SQL DDL import — bring in a .sql dump from any of the eight vendors below. The parser reads CREATE TABLE, CREATE INDEX, ALTER TABLE constraints and table and column comments (COMMENT ON, SQL Server's sp_addextendedproperty), and skips what it does not recognize, so an awkward dump imports partially rather than failing outright
• GraphQL SDL import — bring in a schema from any tool that emits SDL. Object types become tables, scalars map to the diagram's own dialect, and the fields that point at another type become the relationships; the root types and the wrapper types Relay, Federation and Hasura generate are left out rather than drawn as tables
• DBML import — bring in a .dbml file written for dbdiagram.io or dbdocs.io, or emitted by sql2dbml or prisma-dbml-generator. Tables, columns, indexes, enums, header colors, every Ref spelling and each TableGroup arrive; a Project or a sticky Note is skipped rather than refused
• AML import — bring in an .aml file written for Azimutt, in either the v2 or the legacy v1 spelling. Entities, attributes, indexes, enums, colors and every relation arrow arrive; a check and a struct type are skipped rather than refused, and a view arrives as a table
• Imports land laid out — a schema picked from the Import menu or the editor's command palette arrives with its tables placed by their relationships (in rows when it has none), and one undo puts the previous diagram back
• Import and Add — the menu beside Import, and its five formats in the editor's command palette, add a .sql, GraphQL, DBML, AML or .erd.json file to the diagram instead of replacing it: its tables arrive below everything already there, laid out the same way (an .erd.json file keeps its own placement), selected, and one undo takes them away. A table whose name is already taken arrives as a second table rather than merging, and a foreign key to a table outside the file is dropped

Export and code

• SQL DDL export — Databricks, MariaDB, MSSQL, MySQL, Oracle, PostgreSQL, Snowflake and SQLite, from the Schema SQL tab, which saves the DDL as a .sql file or copies it
• Schema SQL options — a panel beside the DDL picks the database and the bracket type, CREATE TABLE IF NOT EXISTS or drop and re-create and a USE or CREATE + USE header, each where the database has it, and the tables by table group, and keeps SQL of your own to write before and after the tables. The statements, header and tables stay with this editor until you close it and never reach the file; the scripts are saved in the document
• Code generation — TypeScript, GraphQL, C#, Java, JPA, Kotlin, Scala, Go, SQLAlchemy, TypeORM, Sequelize, Drizzle, DBML, AML, Mermaid, PHP, Doctrine, Rust, SeaORM, Swift, Zod and JSON Schema, from the Code Generator tab. Its options panel picks the language, the database, the table and column name cases and, for Doctrine, JPA and SeaORM, the bracket type, and saves the code into the vault where your attachments go, with the language's extension
• Export — .erd.json, .sql, .png and .svg, written into the vault where your attachments go (the file explorer lists an .erd.json file only with Detect all file extensions on, see Files); the images from a dialog with a preview: transparent background, light or dark, the PNG at 1x to 3x or copied to the clipboard instead

Find and navigate

• Quick search — Ctrl/Cmd+K opens the editor's command palette to run editor commands (new table, import, export, Auto Layout, tabs, theme, language and more), or to jump to a table after #, a column after @, and a comment or memo after :; Korean also matches by its initial consonants (ㅅㅇㅈ finds 사용자)
• Find and replace — Ctrl/Cmd+F searches table and column names, comments and memos, with match case, whole word and regular expressions, and one undo takes back a Replace All
• Visualization — Graph mode draws a force-directed view of how the tables relate. Flow mode lays them out by their relationships, lights a table you hover and the tables it relates to, and shows names only, keys only or all fields; Focus on this table in a table's right-click menu opens Flow on that table and its neighbours, or, when it is one of several selected tables, as Focus on selected tables on all of them and their neighbours, as Alt+F does for the selection, and neither view writes its layout into the file
• Zoom and pan — pinch a trackpad or two fingers to zoom, drag with the middle button to pan from anywhere, and click the zoom level on the floating toolbar to go back to 100%
• Time travel — replay this editing session's history on the canvas and jump to any point in it, from the toolbar
• Diff viewer — compare the diagram with another .json file from the canvas menu; an .erd diagram goes in as a copy renamed to .erd.json
• Undo / redo — every edit, from the toolbar or Ctrl/Cmd+Z and Ctrl/Cmd+Shift+Z, in the editor's own history

Language and theme

• Display language — the editor's menus, panels, dialogs, command palette and messages in 25 languages, Arabic, Hebrew and Persian laid out right to left while the diagram stays left to right. Pick one from the toolbar's language button or Display Language in the editor's command palette, or System, the default, which follows Obsidian's language (English where the editor has no translation), and the vault keeps the pick (see Settings); table and column names, SQL keywords, data types and generated code stay as they are, and the plugin's own settings and notices stay in English
• Theme — the toolbar's theme builder picks the appearance (System, Light or Dark), a gray color and an accent color, and Theme in the editor's command palette picks the appearance; System, the default, follows Obsidian's light or dark theme and switches with it, and a pick is kept per vault (see Settings)
• Welcome screen — an empty diagram you can edit opens on a menu of New Table, New Memo, Import, Command Palette and Shortcuts, with arrows at the toolbar's search, theme and language buttons and at the floating toolbar where the canvas has room, until its first table, shown memo or shown table group

Collaboration and coding agents

• Coding agents — Claude Code, Codex or any other MCP client edits your diagrams through the ERD Editor MCP server, live on the canvas as one more collaborator; Coding agents below says how

Keeping diffs clean

The canvas scroll position and zoom level, the open tab (Canvas Type in the Lock list), the code generator's language and name cases, and the bracket type are locked in every diagram by default: the file keeps the values they had when locked, so panning around or switching tabs never changes it, and a git history of the vault stays limited to the schema. The editor's Settings tab lists each under Lock with the value the file keeps. Unlock the viewport for a diagram that should open where you left it, or unlock and lock it again to fix a new starting view. Files saved before the locks open with all of them on, their scroll, zoom and tab at the start.

The file holds only what the diagram is: its tables, columns, relationships, indexes, memos, table groups and settings, written in a fixed order, without the measured widths, connector anchors, stacking order or deleted items the editor keeps while it is open. Opening a diagram and closing it without an edit leaves the file as it was, and an edit made on any device, with any fonts, changes only the parts it touches. A file an earlier release of ERD Editor saved is rewritten in this form once, on its first edit.

Split panes

The same diagram can be open in several panes at once, and they stay in sync as you edit in any of them. Keep it in the main window: popout windows are not supported.

Coding agents

A coding agent such as Claude Code or Codex can edit the diagrams in your vault through the @dineug/erd-editor-mcp MCP server. The agent joins the editor like a collaborator: each change shows up on the canvas as it happens, and the agent's undo reverts only its own edits.

Install the MCP server

The server needs Node.js 22.12 or later. npx downloads it the first time the agent starts it, so there is nothing else to install.

Claude Code — run in your vault folder:

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

Codex — add to ~/.codex/config.toml, or to .codex/config.toml in a trusted project:

[mcp_servers.erd-editor]
command = "npx"
args = ["-y", "@dineug/erd-editor-mcp"]

Any other MCP client — run npx -y @dineug/erd-editor-mcp as a stdio server. Start it in your vault folder: it resolves relative document paths against its working directory.

Keep ERD Editor and the MCP server up to date together. When one speaks an older hub protocol than the other, the server refuses to connect and says which one to update.

Edit with an agent

1. Open the vault in Obsidian with the plugin turned on.
2. Start the agent in the vault folder and ask in plain words, for example "Add a reviews table to schema.erd, related to users and products". Name new diagrams with .erd so the file explorer lists them; the agent picks .erd.json when you give no extension.
3. Watch the change land on the canvas. Obsidian saves it about two seconds later, as it saves your own edits; asking the agent to save writes it at once.

A diagram that is not open yet opens in a background tab as soon as the agent opens or edits it, without taking focus from what you are working on. With no VS Code window, Obsidian vault window or JetBrains IDE running ERD Editor that has the document open, or has open the folder, vault or project that holds it, the agent edits the file on disk instead. A vault window counts only while the plugin is enabled; with Coding agents turned off, the agent's writes are refused instead (see the next paragraph).

Settings → ERD Editor → Coding agents, on by default, turns the connection off for the vault. The agent can still read the diagrams from disk, but it never writes one behind the editor, where the next save would overwrite the change. The MCP server's README lists the tools.

Obsidian installed from Flathub runs in a Flatpak sandbox, which the MCP server cannot reach, so its windows never serve the agent, and the agent edits the files on disk unless an editor outside the sandbox, such as a VS Code window, has the document or a folder that holds it open. Obsidian picks the change up as it picks up any change made outside it, and an edit of yours it has not saved yet gives way to the agent's. The plugin says so each time the vault opens, until you turn off Coding agents.

Files outside the vault

The plugin makes no network requests and sends no telemetry. The one connection it accepts is local inter-process communication from an MCP server on this computer, through a socket file or named pipe, never a network port. With Coding agents on, which is the default, each vault window lets that server find it through two files in your home folder, outside the vault:

• ~/.erd-editor/ide/<pid>.json — a lock file, readable by your user account only, naming the vault folder, the diagrams open in the window and a random token the MCP server must present. It is rewritten as diagrams open and close.
• ~/.erd-editor/ide/<pid>.sock — the local socket the MCP server connects to (a named pipe on Windows; in the system temporary folder when the home folder path is too long for a socket).

Both are removed when the window closes or Obsidian quits, and when the plugin is turned off; a reload of the window replaces them. A window that starts also removes the ones windows that have exited left behind, as the ERD Editor extension for VS Code and the ERD Editor plugin for JetBrains IDEs do in the same folder. With Coding agents off, the window keeps only the lock file, with no socket, so an agent still knows not to write the vault's diagrams behind the editor. A window in a Flatpak sandbox writes none of these files and removes none.

Settings

Settings → ERD Editor, kept per vault:

Changing any of the three theme settings re-themes every open diagram immediately. Auto follows Obsidian's light or dark theme and switches with it.

The theme builder in the editor's toolbar changes these same three values and saves them here, so a theme you pick in the editor persists. Its System is Auto: picking a color there keeps the appearance as it is, and Light, Dark or System sets it. Theme in the editor's command palette (Ctrl/Cmd+K) picks System, Light or Dark the same way.

Changing Display language changes every open diagram immediately. Auto follows the language Obsidian shows, and English stands in for one the editor does not offer. The language button in the editor's toolbar and Display Language in that palette (Ctrl/Cmd+K) change this same setting and save it here; their System is Auto. The plugin's own settings and notices stay in English.

Documentation

• Editing Guide — editing, import and export, relationships, quick search, visualization, code generation, settings
• MCP — installing the MCP server, live and headless editing, the 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
• IntelliJ 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

Issues

Found a bug or want a feature? Open an issue. The plugin's source lives in the erd-editor monorepo, in packages/obsidian-plugin.

License

MIT © SeungHwan-Lee