Control Your In-App Fonts with PerAppFonts Xposed Module
The Xposed frameworks gives a tremendous amount of freedom, when it comes to selecting which modules to use. It’s a powerful tool, which offers hundreds of modules available to download as standalone applications. And with a recent update to work with Android 4.4, it’s available to even more users.
The display font is a UI element that is very easy to change. However, changing it on your system partition results in a global change, so every application will use the same font. To prevent such situation, XDA Senior Member zst123 created an Xposed module that allows users to change the font for individual applications.
This module offers 8 different sets of fonts that can be used with applications. These fonts are: Monospace, Serif, Sans, Roboto Condensed, Storopia, Rosemary, Roboto Slab, and the default system font currently in use. Those fonts were seen in various OS revisions such as Gingerbread and KitKat. You can also use custom fonts placed on your SD Card or internal storage. The only requirement is to have Xposed Frameworks installed, and sometimes a reboot is needed. More details can be found in the original thread.
If your in-app fonts are boring, make your way to the original thread and give this module a try.