While Fennec is based on Firefox, the user interface is completely redesigned and introduces a number of new paradigms. It uses touchscreen interaction methods (or the cursor keys, for non-touchscreen handsets) in place of dragging actions with a mouse. Some of the add-ons and plug-ins available for Mozilla Firefox are available for Fennec.

The overall goals for Mobile Firefox are:

• provide Mozilla’s standards-based open-source browser engine, optimized for mobile, that can be embedded by device manufacturers and others;
• a full-featured mobile browser including support for XUL-based add-ons, delivering on Firefox’s key principles of ease-of-use, security and accessibility;
• grow the Mozilla community in the mobile space;
• provide tools and documentation to help developers develop, debug and deploy web applications;
• do all of this work in the shared Mozilla source repositories so all platforms, desktop and mobile, benefit each other