Master Free Online Diagramming with Diagrams (draw.io): A Complete Guide

Introduction

Hello everyone, I'm Su San. Many readers have asked which tool I use to create the clean, eye‑catching diagrams in my articles. This post introduces the free online diagramming tool Diagrams (also known as draw.io) and shows how to use it.

1. Which tool is used?

Commonly used diagram tools include visio and process on, both of which are paid or have limitations. A free, online, powerful alternative is diagrams (also called draw.io), which I use for all my diagrams.

The tool’s website is https://app.diagrams.net/ (formerly https://draw.io/ ). An offline version is available but requires a license, so I mainly use the online version.

2. How to open the diagramming interface?

Enter the website address (e.g., https://draw.io/) in a browser. The first load may be slow while the app initializes.

A dialog appears asking where to save your diagram. Options include OneDrive, Device, Github, and Gitlab. I usually choose Device to store files locally, though saving to Github is also possible.

After selecting the storage location, you choose to create a new diagram or open an existing one. The main canvas then loads.

3. Components of the diagramming interface

The workspace consists of several parts:

3.1 Menu Bar

File

: New, Open, Save, Export, Print, etc. Edit: Undo, Redo, Cut, Copy, Paste, Delete, Find, Replace, etc. View: Default layout, Outline, Layers, Grid, Fullscreen, etc. Arrange: Bring to front, Send to back, Align, Distribute, etc. Extras: Themes, Plugins, Settings, etc. Help: Search, Keyboard shortcuts, About.

3.2 Toolbar

Provides quick access to functions such as zoom, undo/redo, delete, bring forward/backward, background color, font color, connectors, shadows, tables, shapes, fullscreen, expand/collapse, etc.

3.3 Shape Library (left panel)

Shows default shape categories (seven types). Clicking “More Shapes” reveals additional libraries, including iOS and General shapes.

3.4 Canvas (center area)

This is where you build your diagram. Drag shapes from the left panel onto the canvas, copy existing shapes, add grids, and use right‑click context menus for extra options.

3.5 Style Panel (right side)

Allows you to customize selected shapes: line style, fill color, opacity, shadows, text formatting, etc., turning plain shapes into polished graphics.

3.6 Bottom Bar

Displays the current page name. You can add, delete, rename, or reorder pages using the three‑dot menu or the plus button on the right.

Conclusion

Diagrams (draw.io) is a powerful, free online diagramming tool with features such as a comprehensive menu bar, toolbar, extensive shape libraries, customizable canvas, style panel, and page management. This guide covered only a fraction of its capabilities; exploring the tool further will reveal even more possibilities for creating professional diagrams.