API Reference
For developers integrating with GEM or extending it. GEM exposes several distinct surfaces; this section documents each.
REST API
GEM exposes a small, fixed REST surface for external systems: authenticate, read configuration and live state, and dispatch commands or macros. It is mounted under /api on the controller and is gated by the same role permissions as the socket surface.
WebSocket API
The WebSocket connection (Socket.io) is GEM's primary real-time channel — state, subscriptions, commands, and most interactive operations flow over it. The browser/mobile clients talk to it through the GemApp class; server handlers live in gem_client.js.
Web Services
Web Services let you expose custom HTTP endpoints backed by a script you write in the admin interface — for webhooks, third-party integrations, and bespoke APIs that don't fit the standard REST surface. Each service is served under /web_service/.
Macro Scripts
The Run Script macro step executes JavaScript in a sandboxed VM. Use it for logic that doesn't fit the other step types — computing a value, iterating dynamic collections, conditional branching beyond the built-in condition steps, or driving several devices from one place.
Driver Development
A driver teaches GEM to talk to one type of equipment. GEM ships hundreds of drivers; this page is the contract for writing another.