Mermaid for
Entity Relationship (ER) diagrams
Every entity and every relationship in one model
Design a schema, document an inherited one, or align developers and analysts on what lives where.
What is an ER diagram?
An entity-relationship diagram (ERD) models the structure of a database: the entities (things being stored), their attributes (properties), and the relationships between them. The concept was introduced by Peter Chen in 1976 as a framework for database design, and ERDs remain the standard way to plan, document, and communicate data models.
In Mermaid, ER diagrams are text-based and renderable anywhere, which makes them practical for teams who need to keep documentation in sync with a schema that’s always changing.
What you can map
with an
ER diagram
Database schemas and table relationships
Data models for new feature design
API data structures
Legacy system documentation
Multi-service data ownership
CRM or ERP entity relationships
Analytics and reporting data structures
Database schemas and table relationships
Data models for new feature design
API data structures
Legacy system documentation
Multi-service data ownership
CRM or ERP entity relationships
Analytics and reporting data structures
Who uses ER diagrams
on Mermaid
Business Analysts
Translate business entities and rules into a model that both technical and non-technical stakeholders can validate.
When an ER diagram is
the right call
Users, orders, products, and payments, with cardinality and relationships mapped across the full purchase flow.
Organizations, users, roles, and permissions, showing how access is structured across accounts.
Contacts, companies, deals, and activities. The core entities behind a sales pipeline.
Posts, authors, tags, categories, and comments. A lightweight content model for a publishing platform.
Fast, accurate, editable, and actionable.
Describe your idea and get a diagram you can refine, then share with your team instantly.
FAQ
Common questions about building ER diagrams in Mermaid.
