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

Developers

Design your schema before writing a migration, then keep the diagram alongside the code that implements it.

System Architects

Map data ownership across services and teams to catch design conflicts before they hit production.

Data Analysts

Document the data model so every query starts from a shared understanding of what lives where.

Business Analysts

Translate business entities and rules into a model that both technical and non-technical stakeholders can validate.

Consultants

Audit or redesign a client’s data architecture with a diagram that’s clear enough to drive alignment fast.

When an ER diagram is
the right call

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.

FAQ Icon