Your BrewMonday account comes with 2 Device Ids along with their corresponding Auth codes. These devices can represent a Raspberry Pi Gateway, Brew i/o, or a Device Simulator (currently used by developers only).
Raspberry Pi Gateway
A Raspberry Pi Gateway is used for a BrewMonday Gateway as well as your own DIY Raspberry Pi Gateway. A gateway is required for other devices to talk to our cloud, such as a Brew i/o, Bluetooth beacon, Tilt Hydrometer, etc.
This is used for our industrial-grade i/o board. The Brew i/o is based on an Avimesa 1000 and connects to 4-20mA sensors.
A Device Simulator is a developer tool that simulates device data and is really only used in developer accounts.