Mods, short for modifications, are custom-made additions to the Minecraft game that can alter or extend its functionality. They can range from simple tweaks to complete overhauls of game mechanics, adding new items, blocks, or features. Mods can be created by anyone with programming knowledge and can be easily shared with the Minecraft community.

Eaglercraft supports Minecraft resource packs (textures, sounds, language files, fonts).

: Click "Add New" to paste a URL for a mod (often hosted on GitHub) or click "Upload" to select a mod file from your computer.

The standard Eaglercraft server (often called “EaglercraftServer.jar”) is based on an old version of Bukkit/BungeeCord. This means it supports – which are a form of server-side mod.