A guide to FastFlags

FastFlags are Roblox’s version of feature flags, and its goal is to allow Roblox to remotely change how components of the game engine/client work without having to release a new client update every time. They effectively regulate how pre-defined parts of code in the Roblox game client work. Whether it’s specifying which values they work with, activating a feature, or simply bypassing them altogether, etc.

Although FastFlags are usually controlled online, users can also manually change them to adjust how Roblox works. Bloxstrap provides a convenient FastFlag editor tool to make this process easy.

For a list of all available FastFlags in Roblox, you can refer to the scraped FastVariable list or Roblox’s official ClientSettings configuration list.


FastFlags are a powerful tool meant for Roblox engineers. They can be helpful but might cause problems if not used correctly. Only use the flag list editor if you understand how it works and what each flag does. Importing large lists of flags is not recommended because it can lead to stability and functionality issues. If you’re having problems with Roblox, try removing any flags you’ve manually configured in the editor first.

A further look at presets

Bloxstrap offers several preset FastFlags, which are simplified functions that manage FastFlags for you. This section provides more details on what they do and how to use them.

Exclusive Fullscreen

Relevant flag(s): FFlagHandleAltEnterFullscreenManually

This preset is always activated by default and allows you to access Direct3D’s unique fullscreen mode by pressing Alt + Enter rather than F11. Vulkan will always use exclusive fullscreen, regardless. To see if you’re in exclusive fullscreen mode, use Alt + Tab to navigate to another window on the same screens. If Roblox flashes black or un-fullscreens itself, then you were just in exclusive fullscreen.

Using Exclusive Fullscreen mode can lead to various issues, including but not limited to:

  • It might limit its framerate regardless of your settings (but turning off VSync in your GPU settings should solve this).
  • Your mouse cursor may not be visible.
  • The embedded web browser (used for displaying server lists, etc) will not appear (in which case just exit it if you need to use it).

That’s just how things are. If the problems bother you too much, then you’ll have to avoid using it.

DPI scaling fixes

Relevant flag(s): DFFlagDisableDPIScale

This preset resolves the issue of Roblox’s graphics quality decreasing when your screen scaling is above 100%. Here’s a comparison before and after enabling it, using 4K resolution with 300% scaling. If you prioritize performance or battery life, you may choose not to enable this.

Framerate limit

Relevant flag(s): DFIntTaskSchedulerTargetFps

By default, Roblox limits its frame rendering rate to 60 FPS. This flag lets you adjust that limit. If you set it to zero, the option is effectively disabled, and the standard 60 FPS limit will be in effect.

Bloxstrap will automatically set it to match your fastest display. You generally won’t need to change this unless you want to disable it, as explained earlier.


This setting does more than just increase your frame rate limit. There’s a very small chance that changing this setting could cause unintended issues, such as:

  • increased network latency
  • crashes when teleporting/joining games

It does not happen to everyone, but you should check to see whether it happens to you.

Also, some games may rely on your frame rate for precise timing, so increasing it above 60 can affect how these games work. Therefore, ignore the suggestion in the menu and ideally don’t set it higher than 240. If you experience any problems, set the frame rate limit to 0 to reset it to the default value, and check if your issues are fixed.

Preferred lighting technology

Roblox provides developers with different lighting technologies to use in their games. These technologies have been introduced gradually over the years, with each new phase generally offering better visual quality than the previous one, although this improvement often comes at the expense of performance.

A game can only be configured to use a single technology. Developers will frequently use an old lighting technique to accommodate gamers with less powerful hardware. If your hardware can support it, you may consider pushing a newer one to make things look better.


A game’s lighting design is specific to the lighting technology used. Remember that if you override it yourself, you may get lighting difficulties (things being too bright, too dark, etc.). In the majority of cases, this isn’t a problem because everything usually works fine. In some circumstances, well. However, if you ever experience problems with game light, carry this in mind and return the choice to “Chosen by game”.

Escape menu version

If you’re among the users who received the new Chrome UI from Roblox, you’ll have the Version 4 menu enabled automatically, regardless of your preferences. To remove it, you can import this JSON configuration into the flag editor.


“FFlagEnableInGameMenuChromeABTest2”: “False”,

“FFlagEnableReportAbuseMenuRoactABTest2”: “False”


Relevant flag(s): FFlagDisableNewIGMinDUA, FFlagEnableInGameMenuControls

Quite straightforward. Also, in case you’re curious, here’s how they all appear.




Remember, Roblox no longer supports menu versions older than 2023. This means that some buttons and controls might not work as expected, and you may encounter minor visual or usability issues with them.

GUI hiding

Relevant flag(s): DFIntCanHideGuiGroupId

This is a group-based FastFlag, so you need to be a member of a Roblox group for it to function. It can work with any group you’re part of—check the flag editor for instructions. However, if you prefer simplicity and don’t want to deal with setup, just join the Bloxstrap group. Once enabled, this feature offers keyboard shortcuts to show or hide 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 player names, and other BillboardGuis that show up above a player


Pro tip: Ctrl + Shift + G + C + N makes for a nice screenshot 😀

Enabling this will add a freecam option to the menu, but it’s not functional, so you can ignore it.

Old material textures

Relevant flag(s): FStringPartTexturePackTable2022


Roblox is planning to remove this flag, so this option may become unusable. If you’re having issues with old textures, try adding the following JSON config in the flag editor:

{“FFlagMSRefactor5”: “False”}

This option might be removed in a future Bloxstrap update.

Restores the previous material textures used before 2022.

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