Testing on mobile is a crucial part of the development process — the player experience changes when using touch controls, the HUD and UI behave in a different way, and performance limits become painfully evident on lower-end devices. To help pinpoint and eliminate issues, playtest your islands on mobile devices.
The following is a short how-to guide for launching a playtest session on mobile.
On Your Mobile Device
Download the official Fortnite application from your device’s marketplace. If the application is already installed, make sure that it is updated to the latest version.
For the playtest to work, you need to be signed in to the same Epic Games account on your mobile device and your development workstation.
In UEFN
Open your project in Unreal Editor for Fortnite (UEFN).
Click the vertical ellipsis icon next to Launch Session.
Toggle your preferred session options, then select Connect To Platform.
Click Launch Session. If Fortnite is open on your mobile device, you should start seeing the loading screen.
On your mobile device, launch the Fortnite application.
All done! Your UEFN session should load. Play your experience to see how it performs on mobile.
Profiling on Mobile
To understand what causes your island to hitch or run out of memory on mobile, use UEFN’s integrated profiling suite while your workstation and mobile device are connected.
Launch a session using the Connect To Platform option. Ensure the Monitor Performance box is checked.
On your device, run around the island and play the game as intended to continuously capture performance and memory usage data. During gameplay, the Spatial Profiler captures data in real time.
Timing Insights and Memory Snapshot can help you identify the processes and assets that are slowing down your game and causing hitches.
You can use the UEFN MCP to connect an AI agent to your session and assist in identifying and fixing performance issues on your island.
For more information on optimizing your UEFN islands, check out these video tutorials: