Free Sequence Diagram Tool for Mac and Linux: No Install, Works in Any Browser

Most UML tools either require Windows, need Java installed, or ask you to download a desktop application. If you are on a Mac and do not want to install Homebrew and Java just to draw a sequence diagram, or on Linux and tired of hunting for .deb packages that might or might not work on your distro, browser-based tools solve the problem immediately.

Our sequence diagram maker runs entirely in your browser. Open it in Safari, Chrome, or Firefox. Type your diagram. Export it. That is the complete workflow. No install, no configuration, no dependencies.

On Mac: Skip Homebrew and Java Entirely

The typical PlantUML setup on Mac:

1. Install Homebrew (if you do not have it)
2. Run brew install --cask temurin for Java
3. Run brew install plantuml
4. Add PlantUML to your PATH
5. Install a VS Code extension or find an editor

That is five steps before you draw a single line. If you are on a company-managed Mac, you might not even have Homebrew permissions. IT departments lock down software installation for good reasons, and installing a Java runtime is exactly the kind of thing that requires an IT ticket.

A browser-based tool requires one step: open a URL. It works in Safari (Mac's default browser), Chrome, Firefox, Arc, or Brave. The tool uses your browser's built-in rendering engine. No plugins, no extensions, no additional software.

For Mac users who prefer native apps, there are paid options like StarUML and Visual Paradigm. But if you need a quick sequence diagram for a design doc or a README, spending money on a desktop app is unnecessary when a free browser tool does the same thing.

On Linux: Works on Ubuntu, Fedora, Arch, and Everything Else

Linux users know the pain of distro-specific package management. A tool available as a .deb on Ubuntu might not have an RPM for Fedora. Something that works on x86 might not work on ARM. Dependencies conflict. Versions matter.

Browser-based tools sidestep all of this. If your Linux machine runs Firefox or Chrome (and it does), you can create sequence diagrams. No apt-get, no pacman, no flatpak, no snap. The same URL works on Ubuntu 24.04, Fedora 39, Arch, Debian, Mint, Pop!_OS, and any other distribution.

This also means it works on lightweight Linux installations, server distributions with a GUI, WSL with a browser, and Raspberry Pi OS. Anywhere you have a browser, you have a sequence diagram tool.

For developers who prefer terminal-based workflows, you can still use Mermaid's CLI (mmdc) for batch rendering. But for interactive diagram creation where you want live preview and mouse-driven export, the browser tool is the path of least resistance.

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Also Works on Chromebooks, iPads, and Phones

Since the tool runs in a standard browser, it also works on:

• Chromebooks — Chrome is the native browser. The tool runs perfectly. This makes it one of the only sequence diagram options for Chromebook users, since you cannot install traditional desktop software.
• iPads — Safari renders and exports diagrams correctly. The editing experience is usable on an iPad with a keyboard, though it is obviously better on a full-size screen.
• Android tablets — Chrome for Android handles the tool fine. Not ideal for complex diagrams due to screen size, but functional for quick edits.

For Chromebook users in education, this is particularly valuable. Computer science students who only have a Chromebook can create UML sequence diagrams for their assignments without needing access to a "real" computer. Every example from our sequence diagram examples guide works on a Chromebook.

Exporting on Mac and Linux

The tool exports two formats:

PNG — High-resolution raster image. Works everywhere. Paste into Google Docs, Notion, Confluence, PowerPoint, Keynote, email, Slack. The file downloads to your standard Downloads folder.

SVG — Scalable vector graphic. Stays sharp at any zoom level. Ideal for technical documentation, wikis, and README files where the reader might zoom in. SVG files also have smaller file sizes than PNG for simple diagrams.

Both export formats work identically on Mac and Linux. No platform-specific quirks. The browser handles the file download using your system's standard download dialog.

For developers who want the Mermaid source in their documentation, you can also copy the text from the editor and paste it directly into a GitHub or GitLab markdown file inside a mermaid code fence. Both platforms render it natively, no image file needed.

Frequently Asked Questions

Is there a free sequence diagram tool for Mac?

Yes. Our browser-based tool works in Safari, Chrome, and Firefox on Mac with no installation. Type your diagram in Mermaid syntax, see it render live, export as PNG or SVG. No Homebrew, no Java, no downloads.

What is the best UML diagram tool for Linux?

For sequence diagrams, browser-based tools are the easiest option on Linux because they work on every distribution without package management. Our tool runs in any browser and processes everything locally. For full UML suites, Umbrello and StarUML have Linux versions.

Can I create sequence diagrams on a Chromebook?

Yes. Since Chromebooks run Chrome, any browser-based diagram tool works. Our tool renders sequence diagrams from text directly in Chrome with PNG and SVG export. No Android app needed, no Linux container required.