fman build system

Create cross-platform
desktop apps in minutes

fbs lets you create GUI apps for Windows, Mac and Linux.
It is a lightweight alternative to Electron based on Qt and Python.
Save months of development with its cohesive package of best practices.

Electron Alternative

Based on Qt and Python, fbs is lightweight and easy to use. Choose it when Electron's performance is not sufficient. Or when Python is a better fit for you than JavaScript.

Easy Packaging

Unlike other solutions, fbs makes packaging easy. Create installers for your app in seconds and distribute them to your users – on Windows, Mac and Linux!

Open Source

fbs's source code is available on GitHub. You can use it for free in open source projects licensed under the GPL. Commercial licenses are also offered. More information below.


Applications built with fbs have been installed on tens of thousands of machines. It encapsulates years of experience. This ensures your app runs on your users' computers.

Get Started

The best place to get started with fbs is the tutorial. All you need is a text editor and Python 3.5. In 15 minutes, you will create a simple app and an installer. Everybody who takes the tutorial says it's a breeze!


You can use fbs for free in open source projects that are licensed under the GPL. If you don't want to open your code up to the public, you can purchase a commercial license for EUR 249 per developer:

Most fbs projects can use Qt as a library under the LGPL, and thus for free. On the other hand, a commercial license for PyQt is required if your project is not open source. You can avoid this by using fbs with Qt for Python, but support for it is still in the early stages.

Under the Hood

Instead of reinventing the wheel, fbs builds on well-tested solutions: PyQt to use Qt from Python, PyInstaller for packaging, NSIS for Windows installers, .deb files on Ubuntu. With fbs, you don't have to spend weeks integrating these technologies. It addresses common tasks such as shipping resource files and accessing them from within your application. Finally, it solves edge cases that only occur on some users' systems and would take time to figure out yourself.


fbs open sources solutions that were originally implemented for the cross-platform file manager fman. Months of fman's development went into creating installers for the various operating systems, code signing and automatic updates. fbs gives you the same results in minutes instead of months.