Free ERD Builder Online with Chen Notation

Build entity relationship diagrams directly in your browser with a free-form Chen notation canvas. Add entities, attributes, relationships, weak entities, identifying relationships, and ISA subtype structures.

Flexible ER diagram connectors and cardinality labels

Connect shapes with straight lines, drag any connector to create a curve, move each connector head to a different side, and position cardinality or ordinality labels relative to the connector.

Design and export an ERD

1. Add or drag Chen notation shapes onto the canvas.
2. Connect the shapes and customize labels, colors, line styles, text size, and item size.
3. Save the diagram locally, export an editable JSON file, or download a PNG image.

Working from an existing schema? Convert SQL to an ERD or visualize a Prisma schema.