An exporter is a Lua script in the world that writes your game's own files from the world's maps: a server's spawn tables, a client's map data, anything your game reads. It is how an MMO World reaches a game no tool knows about.
Listing exporters
world.json lists each exporter with the script and the folder it writes to. The script runs with access to the world and its maps, and can write only inside that folder.
A new world comes with exporters/example.lua, which writes a spawn table and one JSON file per map into the world's export folder. Copy it as the start of your own.
Running one
On the inspector's World tab, Run runs one exporter. An exporter marked "onSave": true also runs after every save. A message says how many files changed, or what went wrong.
An exporter that writes outside the world's own folder, such as into a game server's data, runs only once you allow it. The first time, GoMMO Studio lists each exporter and the folder it would write to, and asks. Allow only a world you trust, because its scripts came with it. Studio remembers your answer for that world and asks again if an exporter is added or pointed somewhere else.
A script that runs too long or loops is stopped, and the files it had not written yet are left as they were.
What a script can call
The MMO World format page lists everything a script can call, with an example.