A guide to FastFlags
FastFlags are Roblox's implementation of feature flags. They allow you to alter how the Roblox game client functions, based on the flags that Roblox makes available. This page serves as a brief overview on how to add your own flags, as well as detail what each flag preset does.
For a list of every FastFlag that Roblox makes available, see this scraped FastVariable list, or Roblox's official ClientSettings configuration list (browser/raw API).
Roblox loads FastFlags via JSON. For manually overriden FastFlags, they're stored in a file named ClientAppSettings.json, and Bloxstrap features a handy graphical editor in the menu to easily manage these overrides.
Note: do not edit ClientAppSettings.json directly while Bloxstrap is open. Use the menu's FastFlag editor instad.
Bloxstrap provides a number of FastFlag presets, which are simplified functions that handle the FastFlag management for you. This section provides additional information and context on what they do, and how to use them.
Relevant flag(s): FFlagHandleAltEnterFullscreenManually
This preset is always enabled by default, and allows you to use exclusive fullscreen with Direct3D by pressing Alt + Enter instead of F11. Vulkan will always use exclusive fullscreen regardless. You can verify if you're in exclusive fullscreen by switching to another window on the same display with Alt + Tab. If Roblox flashes black momentarily, or un-fullscreens itself, then you were running in exclusive fullscreen.
Relevant flag(s): DFFlagDisableDPIScale
This preset fixes the problem of Roblox's rendering quality decreasing when your display scaling is greater than 100%. Here's a before and after for comparison, at 4K with 300% scaling. If you're more focused on performance, or battery life, you might not want to enable this.
Relevant flag(s): DFIntTaskSchedulerTargetFps
By default, Roblox's frame rendering rate is capped to 60 FPS. This flag allows you to change that cap, with setting a high value effectively uncapping it. Note that this may cause unintended rendering/input-related side effects. If that happens, set the framerate limit as 0 to set it back to defaults, and see if anything changes.
Relevant flag(s): FFlagDisableNewIGMinDUA, FFlagEnableInGameMenuControls
Fairly self explanatory. As the 2020 menu has been abandoned for about three years, some of the buttons and controls may not work properly. Also, if you're wondering, here's what they all look like.
Relevant flag(s): DFIntCanHideGuiGroupId
This is a group-based FastFlag, therefore you must be in a Roblox group for it to work. It can be made to work with any group you're currently in, but the easiest way to make it work is to just join the Bloxstrap group. Here are the following keyboard shortcuts it provides for toggling the visibility of GUI elements.
| Key combination | Action |
|---|---|
| Ctrl + Shift + B | Toggles GUIs in 3D space (BillboardGuis, SurfaceGuis, etc) |
| Ctrl + Shift + C | Toggles game-defined ScreenGuis |
| Ctrl + Shift + G | Toggles Roblox CoreGuis |
| Ctrl + Shift + N | Toggles GUIs that are parented to a player's character |
Relevant flag(s): FStringPartTexturePackTable2022
Brings back the old material textures that were in use prior to 2022.
