Cheat Engine

Cheat Engine is an open source memory scanner and debugger by Eric Heijnen (known as Dark Byte), released under the MIT license. It lets you inspect and modify the memory of running processes, which people mostly use to change values in single player games - infinite health, unlimited money, that sort of thing.

It runs primarily on Windows. Community ports exist for Linux and macOS, but they are less maintained.

Memory scanning

Attach Cheat Engine to a game process, type in the value you want to find (say, your current gold count), hit First Scan, then go back to the game and change that value. Return to Cheat Engine, enter the new number, hit Next Scan, and repeat until you narrow it down to one memory address. Then you change it to whatever you want.

Pointer scanning (Tools > Pointer Scan) finds the chain of pointers leading to an address, which means your cheat survives game restarts instead of breaking every time addresses shift.

Advanced tools

The built in debugger lets you set breakpoints and step through machine code instruction by instruction. The Auto Assembler (Tools > Auto Assembler) lets you write assembly code and inject it into the game's process. There is also a Lua scripting console for automating scans and building cheat interfaces. A speedhack tool (Tools > Speedhack) adjusts game speed from 0.1x to 5x.

Who it is for

Cheat Engine is a tool for single player games and for people interested in learning reverse engineering. Do not use it in multiplayer or online games - you will get banned. For simpler cheat needs, trainers from WeMod or FLiNG require no technical knowledge. If you are learning reverse engineering more broadly, x64dbg is a dedicated debugger worth pairing with Cheat Engine.