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TypeORM to ER Diagram

Q: Which TypeORM features are read?

Decorator-style entities: @Entity, @PrimaryGeneratedColumn, @PrimaryColumn, @Column, the date and version columns, @ManyToOne, @OneToOne with @JoinColumn, and @ManyToMany with @JoinTable. EntitySchema definitions are read too. For exact database types, paste the SQL from typeorm migration:generate instead.

Visualize your TypeORM entities as an interactive ER diagram. Paste the entity classes as they are — @Entity, @Column, @ManyToOne and @ManyToMany are read directly — or paste the SQL TypeORM generates if you want every database-level detail.

Open the diagram tool →

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

ER diagram of the TypeORM example schema: User and Post (2 tables, 1 relationship) — The TypeORM 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 TypeORM entities into an interactive entity-relationship (ER) diagram.
Input: Decorator-style TypeORM entity classes (@Entity, @Column, @ManyToOne, @ManyToMany…), EntitySchema definitions, or the SQL TypeORM generates from them.
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 entity classes — one file or several pasted together.
Paste them into the editor (or drop the .ts file on the page). TypeORM is detected automatically.
Each @Entity becomes a table; @ManyToOne / @OneToOne become foreign keys and @ManyToMany with @JoinTable becomes a junction table.
Arrange, hide tables, then export PNG/SVG or convert to Mermaid/DBML.

Example

Paste TypeORM entities like these:

@Entity()
export class User {
  @PrimaryGeneratedColumn()
  id: number;

  @Column({ unique: true })
  email: string;
}

@Entity()
export class Post {
  @PrimaryGeneratedColumn()
  id: number;

  @Column()
  title: string;

  @ManyToOne(() => User)
  author: User;
}

…and you get User and Post with a relation from Post.authorId → User.id. Try it with your own →

Guide

TypeORM entities are decorators over classes — @Entity(), @PrimaryGeneratedColumn(), @Column(), @ManyToOne(() => User, u => u.posts) — and while this page works from the SQL TypeORM generates, that's the more reliable path anyway: the generated SQL is the ground truth of what's in your database, including column types resolved from your database driver, explicit constraint names, and join tables created by @ManyToMany(() => Tag, tag => tag.posts).

The two easiest ways to get that SQL:

Migrations: npx typeorm migration:generate -d ./migrations MyFirstMigration, then paste the CREATE TABLE statements from the generated file.
Synchronize logging: set logging: true in your DataSource options (or synchronize: true in dev) and copy the schema-sync SQL from the console at startup.

Both produce standard Postgres/MySQL DDL with ALTER TABLE … ADD CONSTRAINT foreign keys, which the parser stitches back onto the right tables. NestJS projects work identically — the entities are plain TypeORM under the hood.

Why use it

Private: everything runs in your browser — nothing is uploaded or stored on a server.
Straight from code: no migration run and no database needed — the entity decorators are read as they are.
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 get an ER diagram from TypeORM?

Paste your entity classes into the editor. Every class marked @Entity becomes a table, its @Column properties become columns, and its relations become foreign keys.

Which TypeORM features are read?

Decorator-style entities: @Entity, @PrimaryGeneratedColumn, @PrimaryColumn, @Column, the date and version columns, @ManyToOne, @OneToOne with @JoinColumn, and @ManyToMany with @JoinTable. EntitySchema definitions are read too. For exact database types, paste the SQL from typeorm migration:generate instead.

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.