IL2CPP
IL2CPP (Intermediate Language to C++) is a Unity-developed scripting backend that converts .NET Intermediate Language (IL) code from scripts and assemblies into C++ code, which is then compiled to native platform code. It serves as an alternative to Unity's older Mono backend, primarily used to improve performance, enable platform support (like iOS where JIT compilation is restricted), and enhance security by obfuscating code. This tool is integral to Unity's build pipeline for deploying games to various platforms, including mobile, console, and desktop.
Developers should use IL2CPP when building Unity projects for platforms that require Ahead-of-Time (AOT) compilation, such as iOS, or when targeting performance-critical applications where native code execution offers significant speed improvements over interpreted IL. It is also valuable for enhancing code security through obfuscation, making it harder to reverse-engineer, and for supporting newer .NET features and platforms that Mono does not fully accommodate. Use cases include high-performance mobile games, console titles, and applications with strict security requirements.