Unlike the standard Java Edition, Eaglercraft runs entirely in your web browser using JavaScript and WebGL. That means traditional .jar mods (Forge, Fabric, etc.) won’t work. However, the community has found creative ways to add mod-like features.
This is the primary way to "add" mods to a vanilla-style Eaglercraft client. EaglerForge allows you to inject JavaScript-based mods (often with a .js extension) directly into the game. eaglercraft 18 mods work
Until then, the only way Eaglercraft 1.8 mods work is via manual injection or pre-compiled clients. Unlike the standard Java Edition, Eaglercraft runs entirely
On the server side (using EaglercraftServer ), admins can install Bukkit/Spigot-style plugins that don't require client mods at all. These give players abilities like: This is the primary way to "add" mods
If you want to add a simple mod like Fullbright or Zoom, here is the safest method: