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A guide to FastFlags

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lekdravpm-del edited this page Aug 12, 2026 · 1 revision

A Guide to FastFlags

FastFlags are hidden settings that control Roblox's behavior. NexusStrap makes it easy to configure them without editing files manually.

What Are FastFlags?

FastFlags are configuration flags that Roblox reads on startup. They control rendering, performance, UI, and more. They're not officially documented by Roblox, but the community has discovered many useful ones.

Using NexusStrap's FastFlags

Quick Presets

NexusStrap provides toggle switches for commonly used flags:

  • Remove Grass — Removes grass rendering for better performance
  • Gray Sky — Replaces the sky with a flat gray color
  • Pause Voxelizer — Disables terrain voxelization
  • Fix Display Scaling — Fixes UI scaling on high-DPI displays

Rendering Mode

Choose between different rendering backends:

  • Automatic — Let Roblox decide (default)
  • Direct3D 11 — Force D3D11
  • Direct3D 10 — Force D3D10
  • Vulkan — Force Vulkan (if supported)
  • Metal — Force Metal (macOS only)

Override Graphic Quality

Force a specific graphics quality level:

  • Automatic — Default behavior
  • Level 1-10 — Force a specific quality level

Advanced Editor

For power users, NexusStrap includes a full FastFlag editor:

  1. Click Open FastFlag Editor at the top of the FastFlags page
  2. Add, edit, or remove individual flags
  3. Use Ctrl+Z and Ctrl+Y to undo/redo changes
  4. Use the Value Selector to quickly choose flag values

Preset Column

The editor includes a "Preset" column that shows which flags have known preset values. This helps identify which flags are safe to toggle.

Flag Count

The editor shows the total number of configured flags, helping you keep track of your changes.

FFlag Templates

NexusStrap includes pre-built flag templates for common use cases:

  1. Go to FFlag Templates in the Settings sidebar
  2. Browse templates by category (Performance, Graphics, Audio, etc.)
  3. Click Apply to activate a template

Auto-Update Templates

You can set NexusStrap to automatically re-apply your template when Roblox updates:

  1. Go to FastFlags
  2. Scroll to Auto-Update FFlag Profiles
  3. Enable Auto-Update on Roblox Update
  4. Select your preferred template

Safety

Anti-Cheat Awareness

Some flags can trigger Roblox's anti-cheat system:

  1. Go to Anti-Cheat in the Settings sidebar
  2. Click Scan Flags to check your current configuration
  3. Flags marked as "High" severity may cause issues

Mod Conflict Detector

NexusStrap detects when two flags conflict with each other:

  1. Go to Conflict Detector in the Settings sidebar
  2. Click Scan for Conflicts
  3. Review any detected conflicts and resolve them

Resetting Everything

If something goes wrong:

  1. Toggle Reset Configuration in FastFlags
  2. This temporarily clears all flags (you can toggle it back to restore)
  3. Or reset permanently by clearing flags manually

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