What are FastFlags in Roblox?
FastFlags in Roblox are allowlisted client settings you can tune for FPS, graphics quality and latency. Each one is a named value the Roblox client reads when it launches, and Roblox originally built them so developers could turn features on or off gradually. A subset of these flags, the ones Roblox permits, is genuinely useful for players who want a higher frame rate or a sharper look. People also write them as FFlags; it means the same thing.
You do not have to memorise flag names to use them. BetterStrap, the Better Roblox bootstrapper, includes a FastFlags editor with presets, and the Roblox FPS unlocker page shows the performance flags it sets for you.
A flag is just a name and a value
Think of a FastFlag as one row in a settings file: a name on the left, a value on the right. For example, a frame-rate flag holds the number of frames you want the client to target. A quality flag might be on or off. The client reads these when it opens, so a change takes effect on your next launch. There is nothing magic underneath, just settings the engine already checks.
What the useful flags control
For players, the flags worth touching fall into three groups. Performance flags set a frame-rate target and how the engine paces frames. Graphics flags adjust lighting, quality and how sharp things look. Networking flags nudge how the client handles latency. Most other flags are internal developer switches with no visible effect, which is why a good editor surfaces only the ones that matter.
Where the allowlist fits in
Roblox maintains an allowlist of flags it is happy for players to set. Editing an allowlisted flag only changes a client setting the platform already exposes, which is why it is not treated as cheating. Anything off that list either does nothing or gets ignored. Roblox does not publish the list, so no tool can promise you are inside it — what a good editor can do is tell you when the client no longer recognises a flag you have set.
