> For the complete documentation index, see [llms.txt](https://dailyjournal.gitbook.io/game-development/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://dailyjournal.gitbook.io/game-development/unity/scripting/unity-architecture.md).

# Unity Architecture

## Mono vs IL2CPP

| Mono (Old)                          | IL2CPP (New)                               |
| ----------------------------------- | ------------------------------------------ |
| Uses Just-In-Time (JIT) compilation | Uses Ahead-Of-Time (AOT) compilation       |
| compiles code on demand at runtime  | compiles entire application before it runs |

> IL2CPP is better at floating point math than Mono.

{% hint style="info" %}
The benefit of using a JIT-based scripting backend is that the compilation time is typically much faster than AOT.
{% endhint %}