---
title: "FastFlag Editor & JSON Import/Export — Bloxstrap Engine & FastFlag Reference"
description: "Configure FastFlag Editor & JSON Import/Export (ClientAppSettings.json) in Bloxstrap via FastFlags → FastFlag Editor. Supported values: Valid FFlag / DFInt / FString JSON keys."
canonical: https://bloxstraplabs.ink/engine/raw-clientappsettings-json-editor
updated: 2026-10-17
---

# FastFlag Editor & JSON Import/Export

Built-in table and JSON modal for adding, searching, importing, and resetting custom FastFlags with syntax validation. Underlying key: ClientAppSettings.json.

## Facts (2026-10-17)

- **Setting:** FastFlag Editor & JSON Import/Export
- **FastFlag Key:** ClientAppSettings.json
- **GUI Location:** FastFlags → FastFlag Editor
- **Supported Values:** Valid FFlag / DFInt / FString JSON keys

## How FastFlag Editor & JSON Import/Export works in ClientAppSettings.json

Built-in table and JSON modal for adding, searching, importing, and resetting custom FastFlags with syntax validation.

When you adjust **FastFlags → FastFlag Editor** inside Bloxstrap, the bootstrapper writes `ClientAppSettings.json` into `ClientSettings\ClientAppSettings.json` before `RobloxPlayerBeta.exe` initializes its renderer.

## Recommended values and stability tips

- **Accepted values:** `Valid FFlag / DFInt / FString JSON keys`. Stick to the built-in GUI preset under [Engine Settings](https://bloxstraplabs.ink/engine) unless you are testing a specific JSON override.
- **Resetting:** If a custom value causes visual artifacts or a startup crash, use [Reset FastFlags to default](https://bloxstraplabs.ink/engine/how-to-reset-fastflags-to-default-bloxstrap).
- **Installer:** Download the latest Windows build of Bloxstrap from [/download](https://bloxstraplabs.ink/download).

## FAQ

### What FastFlag does "FastFlag Editor & JSON Import/Export" control?

It manages `ClientAppSettings.json` inside `ClientAppSettings.json`, accessible directly via **FastFlags → FastFlag Editor**.

### Will this setting reset when Roblox updates?

No. Bloxstrap rewrites `ClientAppSettings.json` into the new Roblox version folder on every launch.

## Related

- [Bloxstrap Engine & FastFlags](https://bloxstraplabs.ink/engine)
- [Best Bloxstrap FastFlags for High FPS & Smooth Frame Pacing](https://bloxstraplabs.ink/engine/best-bloxstrap-fastflags-for-fps-and-low-ping)
- [FastFlags (FFlag, DFInt, FString, FLog)](https://bloxstraplabs.ink/words/fastflags-fflags)
- [Bloxstrap Windows Setup & Installation](https://bloxstraplabs.ink/setup)
- [Framerate Limit / FPS Unlocker (DFIntTaskSchedulerTargetFps)](https://bloxstraplabs.ink/engine/dfint-task-scheduler-target-fps)

## Download

Free Windows app: [Download Bloxstrap](https://bloxstraplabs.ink/download)

Markdown mirror: https://bloxstraplabs.ink/engine/raw-clientappsettings-json-editor.md