How i can send messages to bungee cord from spigot server and back? I can write web api and send requests to it via http, but i think that bungee & spigot contains way to implement this. I'm developing very complex and advanced network, now i have my custom API, but it's nothing without good comunication system.
You can send messages using https://www.spigotmc.org/wiki/bukkit-bungee-plugin-messaging-channel/ but this is not meant for sending a lot of data.