Permission Manager API for Minecraft Forge
Uses AlphAest's PermissionEX mod as the fallback Permission Manager. Even Bukkit Permission managers will work.
If you would like to learn how to use ForgePerms API in your own mod, here is a tutorial https://github.com/legobear154/ForgePerms/wiki/How-to-use-ForgePerms It uses Java Reflect, so please be aware of that.