About Free ER Diagram

Free ER Diagram is an online tool for developers, database administrators, product teams, and students who need to turn SQL table definitions into readable entity-relationship diagrams.

What The Tool Does

• Parses SQL CREATE TABLE statements from common relational databases.
• Detects primary keys, foreign keys, columns, comments, and table relationships.
• Generates ER diagrams in Mermaid and PlantUML formats.
• Supports manual relationships, table grouping, image export, PDF export, backups, and shareable URLs.

Editorial Focus

The site publishes practical database design guides, SQL schema examples, and diagramming tutorials. The goal is to help readers document existing databases, review schema changes, and communicate database structure clearly.

How It Handles User Data

The core tool runs in the browser. SQL input is processed locally, and history is stored locally unless you choose to export or share it.

Project Contact

Questions, corrections, and article suggestions are welcome at joeshanhai@gmail.com.