Plugins

A plugin is a JavaScript module KALLH loads at startup, listed in KALLH_PLUGINS (comma-separated paths or package names). It runs before KALLH serves anything, and can:

• Register an add-on (registerAddon in server/src/addons.ts): an integration that mounts its own API routes and starts its own background jobs (a sync with another booking system, for example). Add-ons can also hook into KALLH’s own flow where it offers a hook, such as before a Stage One run (server/src/stageOneHooks.ts).
• Install a host (installHost in server/src/host.ts): change how KALLH is hosted: where its events and errors go, an operator’s sign-in into the club, the host’s own routes and startup work. A hosting service uses this to run each club in its own container.

Plugins import KALLH’s modules from its compiled server (server/dist/), so they share one database pool, one club and one host with the app they extend. A self-hosted club needs none.