Free Online ER Diagram Generator
Paste your CREATE TABLE DDL and instantly generate an entity-relationship diagram. Visualize your database schema with tables, columns, primary keys, and foreign key relationships — all in your browser, 100% free.
Generate ER Diagram NowWhy Use a Free ER Diagram Generator?
An entity-relationship (ER) diagram is the most intuitive way to understand a database schema. But traditional ER diagram tools require installation, signups, or expensive licenses. Our free online ER diagram generator solves this by working entirely in your browser:
Zero Setup
No installs or accounts. Just paste DDL and generate.
100% Private
Everything runs client-side. Your schema never leaves your machine.
Export PNG
Download your diagram as an image for docs or presentations.
FK Detection
Foreign keys are automatically parsed and drawn as relationship lines.
How It Works
1. Paste Your CREATE TABLE DDL
Copy your CREATE TABLE statements from any database or SQL script. The tool accepts standard SQL DDL syntax used by MySQL, PostgreSQL, SQLite, and more.
CREATE TABLE users ( id INT PRIMARY KEY AUTO_INCREMENT, name VARCHAR(100) NOT NULL, email VARCHAR(255) UNIQUE NOT NULL, created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP ); CREATE TABLE orders ( id INT PRIMARY KEY AUTO_INCREMENT, user_id INT NOT NULL, total DECIMAL(10,2), FOREIGN KEY (user_id) REFERENCES users(id) );
2. Click Generate
Press the Generate Diagram button and the parser extracts each table's columns, data types, primary keys, and foreign key references. The tool supports both inline PRIMARY KEY constraints and table-level PRIMARY KEY declarations.
3. Explore Your Schema
Each table appears as a color-coded card showing its columns with types. Primary keys are marked with a PK badge, foreign keys with an FK badge. Relationship lines connect foreign key columns to their referenced tables. Use the Zoom controls to adjust the view and Export as PNG to save the diagram.
Feature Highlights
- Multi-table support — Parse any number of CREATE TABLE statements in one go. Tables are automatically laid out in a readable grid.
- Primary key detection — Both inline (id INT PRIMARY KEY) and table-level (PRIMARY KEY (id, user_id)) constraints are recognized and highlighted.
- Foreign key mapping — FOREIGN KEY (col) REFERENCES table(col) constraints are drawn as curved, color-coded relationship lines with arrows.
- Column type display — Each column shows its data type (INT, VARCHAR, DECIMAL, TIMESTAMP, etc.) and nullable status.
- Built-in examples — Try predefined schemas for an e-commerce store, blog platform, or library management system to see how the tool works.
- PNG export — Download your ER diagram as a PNG image for inclusion in documentation, presentations, or architecture diagrams.
Use Cases
Database Design & Review
When designing a new database schema, quickly visualize your CREATE TABLE statements to spot missing foreign keys, redundant tables, or normalization issues. The ER diagram generator gives you instant visual feedback on your schema design.
Legacy Database Documentation
Reverse-engineer an existing database by exporting its DDL and pasting it into the tool. The generated ER diagram serves as up-to-date documentation without manual drawing — perfect for onboarding new team members onto an unfamiliar schema.
Interview & Study Preparation
When practicing database design for interviews or studying SQL schema design patterns, use the ER diagram generator to visualize your design and verify relationships between tables. Try schema patterns like many-to-many junction tables, self-referential hierarchies, and polymorphic associations.