Diagram

Need to make a flowchart or diagram real quick?

Simple, fast and just powerful enough web based diagramming tool with sharing functionality. Open source so you can host it yourself and protect your data, access and backups to your hearts content. The keyboard shortcut tool switching is what really makes the this the best option for visually communicating concepts.

Fast, free online mind mapping.

There a few new tools out there to mock up wireframes quickly. I ran through several options and found this one to be by far the simplest and easiest to use. Free for one offs, or pay for more features and an account to store them in.

Write GitHub-flavored markdown and preview the rendered HTML locally. Supports tables, task lists, fenced code blocks, and Mermaid diagrams with sanitized output.

Create flowcharts, sequence diagrams, class diagrams, Gantt charts, and more with live preview, examples, and a built-in syntax cheatsheet.