PlaceholderAPI is a plugin for Spigot servers that allows server owners to display information from various plugins with a uniform format.
Support for specific plugins are provided either by the plugin itself or through expansions. The expansions may be downloaded in-game through the PAPI Expansion Cloud. There are currently over 240+ expansions that support a wide variety of plugins, such as Essentials, Factions, LuckPerms, and Vault.
PlaceholderAPI has been downloaded over 2,000,000 times on Spigot and has been used concurrently on over 50,000 servers, which makes it a must-have for a server of any type or scale.
If you would like to contribute towards PlaceholderAPI should you take a look at our Contributing file for the ins and outs on how you can do that and what you need to keep in mind.
If you would like to create your own Placeholder Expansion for PlaceholderAPI, take a look at our Wiki which contains a detailed tutorial on how you can achieve this.