Whenever you make a change in a Unity project, the Editor will freeze while it swaps in your new code. This process is called a Domain Reload. While it only takes a few seconds in an small project, domain reloads are the bane of all large Unity projects. As a project grows, reloads can take 10 seconds, 20 seconds, and sometimes minutes.

But this doesn’t have to be the case. As an engineer, you have more control over your domain reload times than you might think. Most projects should be able to achieve a 5 second reload time, almost regardless of overall size.

So let’s dig into this a bit, deeper than we usually go. What are the main components of the Domain Reload, and how can we achieve those golden 5 second iteration times?