Server Lock (OverflowBot) — $5

Server-lock is a moderation related feature that allows server managers to lock down a guild via command. This basically kicks anyone that joins while the server-lock is active. Sending a message like pictured below to the kicked user. Once the server lock is toggled off users will be able to join the guild again and not get the boot.

This is the Server Lock extension for Overflow Bot.

Documentation: https://docs.faxes.zone/overflowbot/serverlock