Move as much code as possible to ServerScriptService or ServerStorage . These scripts do not replicate to the player's computer, making them impossible for standard exploiters to steal.
There have been reported exploits where hackers could steal pets currently equipped by players in public servers. To stay safe, many players recommend using private servers or not equipping your most valuable pets in crowded public areas. Verification & Safety Warning Pet Simulator X - Anti Steal Download
Avoid using "free models" from the Roblox Marketplace that might contain hidden "backdoors"—malicious scripts that allow hackers to gain admin access and download your place file. Move as much code as possible to ServerScriptService
Some developers use obfuscation (making code unreadable) or "anti-copy" scripts. However, these are often considered "security through obscurity" and can sometimes be bypassed by determined exploiters. For Players: Preventing Pet Theft To stay safe, many players recommend using private
If you are building a PSX-style game and want to prevent others from downloading or "stealing" your work, keep in mind that anything on the client side can technically be accessed by exploiters.
Some scammers use scripts to lag the game during a trade, making it impossible for you to click "Unaccept" before they remove their pets.