Bloxstrap explained: FPS unlock, fast flags, mods, multi-instance

What Bloxstrap is

Bloxstrap is a third-party launcher for the Roblox PC client on Windows. Instead of opening Roblox through the normal Roblox installer, you install Bloxstrap once, and Bloxstrap handles every subsequent Roblox launch. It downloads new Roblox versions for you, applies optional mods, and exposes a long list of tweaks that the official client hides.

The headline reason most people install Bloxstrap: it bundles an FPS unlocker, a fast-flag editor, and a mod manager in one package, so you do not have to install three separate tools. It is also the cleanest path to multi-instance Roblox (running two or more Roblox clients on the same machine).

Bloxstrap is open-source on GitHub, maintained by the developer pizzaboxer, and free. There is no premium tier, no key system, and no advertising — the project is donation-supported.

TL;DR before we go deeper:

Question	Answer
Where is the official site?	github.com/pizzaboxer/bloxstrap
What platforms?	Windows only.
What does it cost?	Free. Open source.
Does it replace Roblox?	No — it launches the official Roblox client; Bloxstrap is the wrapper.
Will it get my account banned?	No, in normal use. It does not modify the running Roblox process.
What if I uninstall it?	Roblox reverts to the official launcher on the next launch.

The rest of this guide covers what each Bloxstrap feature does, the install path, and which mods are worth turning on.

What Bloxstrap actually does

Bloxstrap replaces the launcher, not Roblox itself. When you click a roblox-player:// link or launch a place from the website, Bloxstrap intercepts the call, applies any configured mods or flags, downloads the latest Roblox client if needed, and then hands off to the real Roblox client. The Roblox client that runs is the unmodified one Roblox shipped; Bloxstrap only changes what happens around it.

That distinction matters for ban risk. Roblox's anti-cheat scans the running client process, not the launcher. Since Bloxstrap exits as soon as Roblox launches (or stays in the tray purely as a configuration UI), it leaves no footprint inside the Roblox process for anti-cheat to flag.

The flip side: any change Bloxstrap makes has to be one Roblox already exposes to a launcher. That includes:

• The FPS cap (rewritten via the same mechanism rbxfpsunlocker uses).
• Roblox's internal "fast flag" feature toggles (read from a config file Roblox already supports).
• Asset replacement (textures, fonts, sounds, models) via Roblox's mod-loading hooks.
• Custom shader chains.
• Multi-instance enablement.

Anything beyond that — script execution, anti-cheat bypass, server-side cheat — Bloxstrap explicitly does not do. It is not an executor.

Installing Bloxstrap

The install is simple and well-tested. Bloxstrap's installer also handles the migration from the official launcher in the same step.

1. Open github.com/pizzaboxer/bloxstrap in a browser. Click the Releases link in the right sidebar.
2. Download the latest Bloxstrap.exe. Do not download from any other site — Bloxstrap is impersonated by knock-off sites that serve modified installers.
3. Run Bloxstrap.exe. The first-run UI opens with a checklist of mods and flags. You can accept defaults and reconfigure later, or click through and customize on first install.
4. Bloxstrap downloads the latest official Roblox client into its own managed folder, applies your selected mods, and hooks the roblox-player:// protocol. The official Roblox launcher in %LocalAppData%/Roblox is left in place; Bloxstrap simply takes priority.
5. Launch any Roblox game from the website or shelf. Bloxstrap's loading screen appears briefly, then Roblox itself opens.

If a Windows SmartScreen warning shows, click More info → Run anyway. Bloxstrap is unsigned but open-source and trusted by the community. SmartScreen will not warn again after the first run on a given machine.

To uninstall: open Bloxstrap → Settings → Uninstall. Bloxstrap removes itself and restores the original Roblox launcher hook. There is no left-over residue.

The features worth turning on

Bloxstrap is configurable to the point of overwhelming. The five settings that actually move the needle for most users:

FPS Unlocker

Lifts the 60 FPS cap. Identical to running rbxfpsunlocker separately. Set the cap to your monitor's refresh rate (60 / 75 / 120 / 144 / 165 / 240) or to 0 for unlimited. The default Bloxstrap unlocker is built in, so you do not need a second tool.

If you already have rbxfpsunlocker installed, uninstall it before enabling the Bloxstrap unlocker — two tools fighting over the same memory address can cause cap flicker.

Fast Flags

"Fast flags" are internal Roblox feature toggles that the company uses for A/B testing, gradual rollouts, and developer-only experiments. Bloxstrap exposes them through a config UI. Useful flags include:

• FFlagDebugGraphicsPreferD3D11=true — force the DirectX 11 renderer (rarely beats the default but stable on older GPUs).
• DFIntTaskSchedulerTargetFps=144 — secondary FPS hint to the engine scheduler. Pair with the unlocker.
• FFlagDisableNewIGMinDUA=true — disable the new in-game menu UI if you prefer the old one.
• FIntCameraMaxZoomDistance=2000 — raise the camera zoom-out limit.

Fast flags are documented at bloxstrap.app/flags (Bloxstrap's docs site). Do not paste random flags from forum posts you cannot verify — some are deprecated and break the client.

Mod Manager

Replaces textures, sounds, fonts, and 3D models. Common uses:

• Custom death sound.
• Smooth/recolored UI fonts.
• Vintage Roblox textures (the pre-2014 "PBR-off" look).
• Reskin the loading screens.

Mods are zipped into a single folder and dropped into Bloxstrap → Mods. They live alongside Roblox locally; nothing is sent to the server, so no other player sees your mods. Mods that change gameplay-relevant assets (avatar accessories, gun models) can render visibly differently for you vs. for other players, which is fine for cosmetic mods but means you should not expect "modded gameplay" to actually change game state.

Multi-Instance

Lets you run two or more Roblox clients on the same Windows machine simultaneously. Roblox blocks this in the default launcher; Bloxstrap unlocks it via a small Windows mutex workaround.

Use cases: testing your own game with multiple accounts, AFK-farming on two accounts at once, playing a co-op experience with yourself, or running scripted helpers (alts that follow you around).

Roblox does not enable multi-instance because it makes alt-account farming easier, but the feature itself is not against ToS — you are not modifying the client, just opening two of them. Account farming and exploit-stacking on alts will still get the alts banned.

Custom Bootstrapper UI

Cosmetic. Replaces Bloxstrap's launcher screen with a custom theme (dark mode variants, retro Roblox-2014 loading screen, anime-style transitions, etc.). Community-built themes are linked from the Bloxstrap Discord. Pure aesthetics, no functional change.

The ban risk question

Short version: using Bloxstrap with the default configuration carries no meaningful ban risk.

Longer version:

• Bloxstrap itself — not flagged. It exits before Roblox loads. Anti-cheat never sees it.
• FPS unlocker — not flagged in 2026. Roblox's anti-cheat treats memory-write of the FPS cap as benign (it does not change game state).
• Fast flags — never flagged. They are Roblox's own feature toggles; you are setting them client-side the same way Roblox does internally.
• Mod manager (cosmetic mods) — not flagged. Asset replacement is local-only and Roblox knows about it (the mods folder is a documented Roblox feature).
• Multi-instance — not flagged by itself. What you do with the alt accounts (exploit, farm, scam) is what gets the alts banned, not the multi-instance act.

There is no documented case of an account ban traceable to Bloxstrap with default settings. The configurations that have caused bans are: aggressive multi-instance + alt farming, fast-flag changes that disable client-side anti-cheat hooks (mods reverse-engineered for that purpose), and combining Bloxstrap with a script executor in the same session.

Bloxstrap vs. the alternatives

For a long time the main competitor was a launcher called Fishstrap (a Bloxstrap fork). Both projects share most of their codebase. Bloxstrap is the more actively maintained option in 2026 — Fishstrap exists but updates more slowly.

For users who only want one thing:

• Only the FPS unlocker — Install rbxfpsunlocker directly. Smaller, simpler, no launcher hooks.
• Only fast flags — Edit Roblox's ClientSettings.json manually. Bloxstrap is just a UI on top of this.
• Only multi-instance — There are standalone multi-instance utilities, but Bloxstrap is the cleanest single-package option.
• All of the above plus extras — Bloxstrap.

bloxyblox also carries a standalone FPS unlocker guide for users who do not want a launcher in the mix.

Frequently asked

Q. Will Bloxstrap get my account banned? With default settings, no. Aggressive multi-instance + alt-farming changes that calculus.

Q. Does Bloxstrap work on Mac or Linux? No. Windows only. The Mac Roblox client uses a different bootstrap chain that Bloxstrap does not hook.

Q. Roblox auto-updated and now Bloxstrap is broken. Bloxstrap usually detects new Roblox versions and migrates automatically. If the auto-migration fails, open Bloxstrap → Settings → "Reinstall Roblox" and let it re-pull the current client.

Q. Will Bloxstrap install malware? The version from github.com/pizzaboxer/bloxstrap is open-source, auditable, and clean. Versions from any other site are unsafe by default. The source code is on GitHub; you can compile it yourself if you want zero trust in the maintainer's binary.

Q. Can I use Bloxstrap with an executor? Technically yes, but the combination is what raises ban risk, not Bloxstrap alone. Run Bloxstrap on the account you care about; run the executor on a separate alt.

Q. Why is the SmartScreen warning so scary? Because Bloxstrap is unsigned (signing certificates cost thousands of dollars per year, which a donation-funded open-source project does not pay for). The warning is generic and triggers on every unsigned executable, not specifically on Bloxstrap.

Q. Bloxstrap launches but Roblox crashes immediately afterward. Almost always a fast flag conflict. Reset all flags to default in Bloxstrap → Fast Flags → Reset, then re-enable them one at a time to find the bad one.

Q. Is there an iOS / Android Bloxstrap? No. Roblox mobile uses a completely different runtime that has no equivalent of fast flags or mods. Bloxstrap is fundamentally a Windows-launcher concept.

If Bloxstrap is misbehaving after the steps above, the issue is almost always (1) a bad fast flag from a forum post, (2) a Roblox client mid-update, or (3) Defender quarantining the Roblox executable. Reset flags, let Roblox finish updating, and add the Bloxstrap folder to Defender exclusions — that fixes the vast majority of issues.