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What you're asking for is illegal and impossible from a technical standpoint.

Even though it's a video game, backdooring servers is a form of unauthorized access, and you can get in trouble for it, even if the risks are low. I highly recommend using client-side cheats which are legal and do not use backdoors from infected assets.

There is a difference between the game developer intentionally adding a backdoor compared to them using an infected asset which injects a backdoor into their game. If there is intent by the developer to implement a backdoor, then they acknowledge those risks and it's legal to use. In your case, you are talking about infected assets which means there is no intent or implicit permission, making it unauthorized access.

The reason I say this is because unauthorized access to the server can lead to theft of data such as API keys and intellectual property, so it is of valid grounds to be considered illegal. Client side cheats do not gain unauthorized access since every game developer in Roblox should assume that the client had access to whatever was replicated to it.

On the technical side, you cannot do this because you would require HTTP access to make HTTP requests. The only way to do this would be to send your requests to a client through a communication channel that is not HTTP that can make HTTP requests on your behalf.

Nothing comes off the top of my head other than setting up a bot on the game that can act as a proxy by using RemoteEvents. This solution is not feasable as it makes the server vulnerable to MITM attacks.

There's a bunch of serversides out there and not exactly they are illegal, the owner of the game need to load the model into the game.

Just want a way to make it more, silently.