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Sequelize to ER Diagram

Q: How do I diagram Sequelize models?

Paste your sequelize.define or Model.init definitions. Columns come from DataTypes and relations from associations like belongsTo / hasMany.

Paste your Sequelize model definitions and get an interactive ER diagram — tables, columns from DataTypes, and relations from associations.

Open the diagram tool →

No signup · nothing uploaded · export PNG / SVG / Mermaid / DBML · shareable link

ER diagram of the Sequelize example schema: User and Post (2 tables, 1 relationship) — The Sequelize example below, drawn by the tool: User and Post (2 tables, 1 relationship).

At a glance

What it is: SQL to ER Diagram is a free, open-source browser tool that turns Sequelize models into an interactive entity-relationship (ER) diagram.
Input: Sequelize model definitions (JavaScript source).
Output: An interactive ER diagram you can rearrange, then export as PNG, SVG, Mermaid, DBML or PlantUML, or share as a link.
Cost: Free. MIT-licensed open source. No account or signup.
Privacy: Runs entirely in your browser. The schema is never uploaded, and share links carry the diagram in the URL fragment, which is not sent to a server.
Limits: It never connects to your database itself: you paste schema text, or run one read-only catalog query in your own client and paste the result. There are no accounts, so there is no real-time multi-user editing; diagrams are kept in your browser, as a saved file, or as a share link. Layout stays smooth at around 300 tables.

How it works

Copy your Sequelize models (sequelize.define(...) or Model.init(...)).
Paste them into the editor — Sequelize is auto-detected.
Each model becomes a table; associations like belongsTo become relations.
Arrange, hide tables, then export PNG/SVG or share a link.

Example

Sequelize models like this:

const User = sequelize.define('User', {
  email: { type: DataTypes.STRING, unique: true }
});

const Post = sequelize.define('Post', {
  title: DataTypes.STRING
});

Post.belongsTo(User);

…renders User and Post with a relation between them. Try it with your own →

Guide

Sequelize models can be defined three ways — sequelize.define('User', {...}), class User extends Model {} + User.init({...}), or the old sequelize.import — and this page reads all of them as plain text. Attribute names come from the object keys, types from the DataTypes values, and primaryKey: true, unique: true, allowNull: false are picked up as key/constraint badges.

Relations are drawn from your associations: Post.belongsTo(User) and User.hasMany(Post) both produce the same edge (the foreign key is what matters), belongsToMany through a model renders as many-to-many via the join table, and alias options like { as: 'author', foreignKey: 'author_id' } are respected when naming the edge.

An alternative that captures the real database: call await sequelize.sync({ logging: console.log }) once against a scratch database and paste the logged CREATE TABLE SQL instead. That shows exactly what Sequelize would build, including the join tables it creates implicitly for belongsToMany.

Why use it

Private: everything runs in your browser — nothing is uploaded or stored on a server.
Interactive: drag tables, auto-arrange, hide noise, add notes, and manually link columns.
Export a high-res PNG, vector SVG, or the schema as Mermaid / DBML / PlantUML code.
Free & open source — no account, no sign-up.

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FAQ

How do I diagram Sequelize models?

Paste your sequelize.define or Model.init definitions. Columns come from DataTypes and relations from associations like belongsTo / hasMany.

Is my schema uploaded anywhere?

No. Everything runs locally in your browser — your schema is never uploaded to or stored on any server.

Is it free?

Yes. It is completely free and open source, with no account or sign-up required.