Skip to content

Welcome to DiagramaHub

DiagramaHub is an open-source platform (Apache 2.0) to create, organize and export diagrams written as text: Mermaid, PlantUML, D2 and DBML, plus a freehand whiteboard for sketching. It includes an AI assistant built on BYOL (Bring Your Own LLM): you supply your provider's API key and DiagramaHub uses it to generate, improve, fix and explain diagrams through a chat.

It runs on your own infrastructure with Docker Compose.

Beta software (v0.x)

APIs and data structures may change between versions. Check the release notes before upgrading.

Where do I start?

  • I want to use DiagramaHub

    Create your first project and learn the editor and the four diagram languages.

    User guide

  • I want to run it on my server

    Installation, environment variables, production, integrations and backups.

    Self-host

  • I want to develop or contribute

    Architecture, backend modules, frontend, API, testing and how to extend it.

    Development

  • I want to review security

    Authentication, MFA, protections, audit log and how to report issues.

    Security

Features

Diagrams as code

  • Four languages: Mermaid (rendered in the browser), PlantUML, D2 and DBML (rendered on the server with Kroki, inside your own installation).
  • Monaco editor with syntax highlighting and a live preview.
  • Per-diagram styling: themes, layout engines, classic or hand-drawn look and curve types in Mermaid; themes and skinparam in PlantUML; themes in D2; background color and pattern for all.
  • Conversion between languages with AI, with a side-by-side preview.
  • Presentation mode in full screen.

Freehand whiteboard

  • Whiteboard canvas with shapes, arrows, text and freehand strokes, drawn with a hand-drawn look.
  • Element locking, undo/redo and PNG export.
  • Sketch → Mermaid: turn a sketch into an editable Mermaid diagram.

Organization

  • Projects and folders with a file explorer: rename, duplicate, move between folders and between projects.
  • Export a diagram to PNG, SVG, PDF or Markdown.
  • Export a project or a folder as a ZIP or as Markdown meant as context for AI.
  • Import diagram files, ZIP archives and Excalidraw drawings.

AI assistant (BYOL)

  • Five providers: Google Gemini, OpenAI, Anthropic Claude, DeepSeek and MiniMax. Your API key is stored encrypted and is never returned in full.
  • Per-diagram chat to generate, improve, repair or explain, with validation of the generated code and optional automatic fixing.

Sharing

  • Public or protected links with an access code, expiring after 5, 10 or 30 days or never, with the option to show or hide the source code.

Accounts, security and administration

  • Sign-up with a strong password, MFA (TOTP app and email codes, with recovery codes) and Google sign-in.
  • Plans and limits defined by the operator, with optional payments through Stripe.
  • Admin panel: users, plans and integrations (email, payments, OAuth).
  • Audit log of security events.
  • Spanish and English UI, with light and dark mode.

How it is built

flowchart LR
    U["Browser"] --> F["Frontend<br/>React + Vite"]
    F -->|"REST API /api/v1"| B["Backend<br/>FastAPI"]
    B --> M[("MongoDB")]
    B --> K["Kroki<br/>PlantUML · D2 · DBML"]
    B -.->|"your API key"| AI["AI provider"]

Four Docker Compose services: frontend, backend, Kroki and MongoDB (which can be external). See Architecture for the details.

To serve this documentation locally:

pip install -r docs/requirements.txt
mkdocs serve