draw.io — Free Browser-Based Diagramming and Whiteboarding Tool

Introduction

draw.io (also known as diagrams.net) is a free, open-source diagramming tool that runs entirely in the browser. It supports a wide range of diagram types including flowcharts, network diagrams, UML, ER diagrams, and org charts. Files can be saved to local storage, Google Drive, OneDrive, or GitHub without creating an account.

What draw.io Does

• Creates flowcharts, UML diagrams, network diagrams, ER diagrams, and architectural drawings
• Stores diagrams in an open XML format compatible with version control systems
• Integrates with cloud storage providers including Google Drive, OneDrive, and Dropbox
• Exports to PNG, SVG, PDF, VSDX (Visio), and other formats
• Provides VS Code and Confluence/Jira integrations for developer and team workflows

Architecture Overview

The application is a client-side JavaScript app built on the mxGraph library. All rendering and editing happens in the browser with no server-side processing of diagram data. The server component only serves static assets and handles OAuth flows for cloud storage integrations. This architecture ensures that diagram content never leaves the user's device unless explicitly saved to a cloud provider.

Self-Hosting & Configuration

• Run the official Docker image for a fully self-contained deployment
• Serve the static web app from any HTTP server for an even simpler setup
• Configure allowed storage backends via environment variables
• Disable cloud storage integrations for air-gapped or compliance-restricted environments
• Embed in Confluence, Jira, or Notion using official marketplace integrations

Key Features

• No account, no signup, and no tracking — works instantly in any modern browser
• Offline support via Progressive Web App capabilities
• Hundreds of built-in shape libraries covering IT, engineering, and business domains
• Import and export Visio (VSDX) files for interoperability with enterprise tools
• Real-time collaboration when using shared storage backends like Google Drive

Comparison with Similar Tools

• Lucidchart — commercial SaaS diagramming; draw.io is free and self-hostable
• Excalidraw — whiteboard-focused with a hand-drawn aesthetic; draw.io is more formal and feature-rich
• Mermaid — text-based diagrams rendered from code; draw.io provides a visual drag-and-drop editor
• PlantUML — text-based UML generation; draw.io supports UML visually with more control over layout

FAQ

Q: Is draw.io really free? A: Yes. The web app and desktop app are completely free with no premium tiers. Revenue comes from Confluence and Jira marketplace integrations.

Q: Can I use it offline? A: Yes. The desktop app (available for Windows, macOS, and Linux) works fully offline, and the web app supports offline mode via service workers.

Q: What file format does it use? A: Diagrams are saved as compressed or uncompressed XML, which is text-based and works well with Git version control.

Q: Does it support real-time collaboration? A: Multi-user editing works when diagrams are stored on Google Drive or other shared backends. There is no built-in collaboration server.

Sources

• https://github.com/jgraph/drawio
• https://www.drawio.com