FastFlags

FastFlags (FFlags) are internal Roblox configuration values that control engine behavior. AppleBlox lets you set custom flags through the Engine page.

WARNING

Roblox now uses a whitelist for FastFlags. Many flags that used to work are silently ignored by the client. This is a Roblox-side restriction, not an AppleBlox bug.

Preset Settings

The Engine page offers visual controls for common flags:

• Graphics API - OpenGL, Metal, or Vulkan
• Graphics Quality - Quality level slider (when enabled)
• Level of Detail - Toggle mesh LOD
• Fractional Scaling - Toggle fractional display scaling
• FPS Cap - Maximum framerate

Custom Flags

The flag editor gives you full control over any FastFlag:

• Add flags manually by name and value.
• Import/Export as JSON, useful for sharing flag profiles.
• Enable or disable individual flags without removing them.
• Search and filter your flag list.
• Batch operations - Select multiple flags to enable, disable, or delete at once.

Import Format

{
    "FFlagExampleFlag": true,
    "DFIntAnotherFlag": 120
}

Flags are written to Roblox's ClientAppSettings.json at launch.