ER Diagram Generator — type entities, get a clean ERD
Make an entity-relationship diagram online by typing plain text. Declare entities, attributes, and relationships — the ERD renders live with a presentation-ready layout, crow's-foot notation included. Free, no signup, exports to SVG and PNG.
This is a quick preview. The full editor adds AI generate, save & share links, every theme, and watermark-free HD export.
Open full editor →What is an ER diagram?
An entity-relationship diagram (ERD) models the data in a system: entities (tables) with their attributes, and the relationships between them with cardinality — one-to-one, one-to-many, many-to-many. Crow's-foot notation encodes cardinality on the connector ends, so a reader can see "a customer places many orders" without reading a schema dump.
Common use cases
Sketch tables and relationships before writing migrations — cheaper to argue about a diagram than about a deployed schema.
A current ERD answers the new teammate's first question — what data do we have and how does it connect — in one picture.
Model the entities a new feature touches to expose missing relationships and ownership questions before implementation.
Syntax quick reference
The essentials to get productive — paste any of these into the editor above and adapt. For the full grammar, see the ER diagram syntax reference.
| Syntax | What it does |
|---|---|
CUSTOMER ||--o{ ORDER : places | One customer, zero-or-many orders — crow's-foot cardinality on each end. |
|| | Exactly one. |
o{ | Zero or many. Also: |{ one-or-many, o| zero-or-one. |
CUSTOMER { int id PK } | Entity block listing typed attributes; mark keys with PK / FK. |
: "appears in" | Relationship label — quote it when it contains spaces. |
Export options
Vector output with fonts inlined — crisp at any zoom, right for docs, READMEs, and the web.
Raster with optional transparent background and up to 4× scale — right for slides and tickets.
One click publishes a share page with the beautified diagram — no file juggling for reviews.
Frequently asked questions
How do I make an ER diagram online for free?
Type your entities and relationships as text in the editor above — one line per relationship, plus optional attribute blocks. The ERD renders live with crow's-foot notation and a clean layout, and exports to SVG or PNG without signup.
What do the crow's-foot symbols mean?
The connector ends encode cardinality: || is exactly one, o| is zero-or-one, |{ is one-or-many, o{ is zero-or-many. So CUSTOMER ||--o{ ORDER reads "one customer places zero or many orders".
Can I show table columns and keys?
Yes. Add an attribute block after the entity name — each row is a type and a name, with optional PK or FK markers. The preloaded example shows three entities with typed columns; edit it in place to see the blocks re-render.
Is this a database design tool or just a drawing tool?
It is a diagramming tool with schema-aware syntax: because the source is text, it diffs in version control and stays reviewable in pull requests — but it does not connect to a live database or generate SQL migrations.
Can I generate the ERD from AI output?
Yes. Ask any AI assistant for "a Mermaid erDiagram of …", paste the code here, and it renders with a beautified layout. A command-line tool and editor plugins let agents and scripts export diagrams directly.
Is this ER diagram maker really free?
Yes. Anonymous use covers live preview, beautify, and SVG/PNG export with a small watermark; a free account removes the watermark. Per-month export quotas are listed on the pricing page.
Ready to make your own?
Open the full editor to save your work, switch themes, and export clean SVG or PNG. No signup.