What is sober-fastflags?

This repository is a reference guide, not software you run. It documents Roblox FastFlags, internal engine settings that control rendering and stability, specifically for people who use Sober, a compatibility layer that runs the Android version of Roblox natively on Linux desktops. Sober is distributed as a Flatpak package and uses Vulkan for graphics by default, falling back to OpenGL when needed. Its settings live in a config file inside the user's home folder, and can also be opened through a graphical settings menu. Since late September 2025, Roblox only allows a small approved list of these flags to be changed locally, so older community guides that reference other flags no longer work. This guide only lists flags confirmed to still be on that approved list, grouped into three areas: rendering and performance, such as how far away detailed models switch to simpler versions and how much anti aliasing is applied, stability and video memory, such as texture quality settings that prevent out of memory crashes, and smaller interface and comfort settings like grass animation intensity. The guide explains a specific problem with Sober on Linux: because it runs an Android build of Roblox inside a desktop Flatpak environment, requesting high quality textures can quickly use up a graphics card's dedicated memory. Unlike on Windows, Linux systems, especially with proprietary NVIDIA drivers, do not reliably fall back to system memory when this happens, which can cause an immediate out of memory crash. The fix described is to manually cap texture quality to a medium or low setting. Rather than asking the reader to tune every flag by hand, three ready made presets are provided: one aimed at low end graphics cards or systems hitting memory crashes, one balanced preset for mid range GPUs, and one for maximum visual fidelity on high end systems with plenty of video memory. Each preset is a small JSON block that can be pasted directly into Sober's configuration file. The guide also covers deprecated flags and anti cheat risk considerations, and is translated into several languages beyond English.