ER Diagram Generator

Generate entity-relationship (ER) diagrams and database schemas online — free, using Mermaid syntax or AI prompts.

What is an ER Diagram?

An Entity-Relationship (ER) diagram is a visual representation of a database schema. It shows the tables (entities), their columns (attributes), and the relationships between them. ER diagrams are essential for planning database architecture and communicating data models to stakeholders.

Use Cases

• Database Design: Plan your schema before writing migrations. Catch relationship issues early.
• Documentation: Add ER diagrams to your project wiki or README.
• Code Reviews: Include schema diagrams in PRs that change the database.
• Client Communication: Show stakeholders how data is structured without raw SQL.

Mermaid ER Diagram Syntax

Use the erDiagram keyword. Define entities with attributes (PK, FK annotations). Specify relationships: ||--o{ (one to many), }o--o{ (many to many). Describe your schema to the AI and it generates the erDiagram code instantly.