There are several types of mods for 7 Days to die. Below are a few general descriptions to give you a better understanding of their use and function.
A modlet is a mod that adds, subtracts or tweaks the basic (vanilla) game on a small scale. These are typically XML edits that are uploaded to the server’s Mods folder. The server then pushes the changes to the client game, which means these do not need to be downloaded by players.
If you want to make your own modlets, start by checking out Xpath Modding Explanation Thread.
An overhaul mod is a large mod that overhauls the base game. Overhaul mods tend to be, but not always, DMT mods. The DMT mods inject new code into the csharpassembly.dll used by 7 Days. DMT mods are not Easy Anti-Cheat (EAC) friendly and EAC must be disabled to run them. Mods that introduce new assets need to be downloaded locally by players. The most common and popular overhaul mods currently are Ravenhearst and Darkness Falls.
Admin tools are server-side tools used to help with server administration. The most common admin tools are Alloc’s server fixes, Bad Company Manager (BCM), CSMM Patrons Mod (CPM), and Server Tools (ST). These are also known as APIs.
These work by adding commands to manage the server. While most have some overlapping features each one also tends to have their own unique features as well.