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Mermaid to ERD

Paste a Mermaid erDiagram and turn the text into a fully interactive ERD — drag tables, auto-arrange, and export to image, DBML or PlantUML.

Open the diagram tool →

No signup · nothing uploaded · export PNG / SVG / Mermaid / DBML · shareable link

ER diagram of the Mermaid to ERD example schema: CUSTOMER and ORDER (2 tables, 2 relationships) — The Mermaid to ERD example below, drawn by the tool: CUSTOMER and ORDER (2 tables, 2 relationships).

At a glance

What it is: SQL to ER Diagram is a free, open-source browser tool that turns a Mermaid erDiagram into an interactive entity-relationship (ER) diagram.
Input: A Mermaid erDiagram block.
Output: An interactive ER diagram you can rearrange, then export as PNG, SVG, Mermaid, DBML or PlantUML, or share as a link.
Cost: Free. MIT-licensed open source. No account or signup.
Privacy: Runs entirely in your browser. The schema is never uploaded, and share links carry the diagram in the URL fragment, which is not sent to a server.
Limits: It never connects to your database itself: you paste schema text, or run one read-only catalog query in your own client and paste the result. There are no accounts, so there is no real-time multi-user editing; diagrams are kept in your browser, as a saved file, or as a share link. Layout stays smooth at around 300 tables.

How it works

Copy your Mermaid erDiagram.
Paste it into the editor — Mermaid is auto-detected.
Entities become draggable tables; relationships are drawn with cardinality.
Arrange, then export PNG/SVG or convert to DBML/PlantUML.

Example

A Mermaid erDiagram like this:

erDiagram
  CUSTOMER ||--o{ ORDER : places
  CUSTOMER {
    int id PK
    string name
  }
  ORDER {
    int id PK
    int customer_id FK
  }

…becomes an interactive ERD with CUSTOMER linked to ORDER. Try it with your own →

Guide

Mermaid renders your erDiagram as a fixed SVG — you take what the layout engine gives you. Paste the same block here and it becomes a real ERD canvas: entities are tables you can drag into place, relationships re-route as you move things, and the whole picture stays consistent when you edit it.

The typical flow: copy the erDiagram out of your README or design doc, paste, untangle the layout (auto-arrange first, then drag the exceptions), and export an SVG that actually fits the slide. Along the way you can convert the Mermaid into DBML — handy when the sketch graduated into a real schema that lives in a DBML-based tool.

Supported syntax: all nine cardinality combinations (||, o|, }o, ||… on both ends), attribute blocks with PK/FK/UK key markers, quoted relationship labels, and entities referenced before they're defined. If your block renders in GitHub, it will parse here — the grammar is the same, the output is just editable.

Why use it

Private: everything runs in your browser — nothing is uploaded or stored on a server.
Interactive — not a static image; drag and rearrange freely.
Convert Mermaid to DBML, PlantUML, PNG or SVG.
Free & open source — no account, no sign-up.

MermaidDBMLPlantUMLPNG / SVG

FAQ

How do I turn Mermaid text into a diagram I can edit?

Paste the Mermaid erDiagram here — it renders as draggable tables you can arrange, then export as an image or convert to DBML/PlantUML.

Is my schema uploaded anywhere?

No. Everything runs locally in your browser — your schema is never uploaded to or stored on any server.

Is it free?

Yes. It is completely free and open source, with no account or sign-up required.