The Elgato Key Light and Key Light Air are edge-lit LED video lights that are popular with live streamers on platforms like Twitch. These lights are IoT devices and are normally controlled with Elgato's 'Control Center' app or through one of the Stream Deck devices (also manufactered by Elgato). The Key Light devices do not natively support third-party integration, but they can be controlled by directly interfacing with the lights' built-in API.

The 'Control Center' app sends commands to Key Light devices it has been associated to over HTTP. The API requests defined in this document were found using Wireshark and reference version 1.1.2 of the Elgato 'Control Center' app (Windows 10).

After being added to a network, Key Light devices likely receive IP addresses from a router via DHCP. Specific IP addresses can be pulled from the DHCP server / network router, but they are also easily accessible in the 'Control Center' app. To do this:

1. Launch / Open the 'Control Center' app
2. Click on the Accessory settings icon (shaped like a slider) next to a device's name
3. Expand the Advanced section. IP Address will be presented under Power On Behavior and Firmware Version

Key Light devices listen for commands on port 9123.

All requests should be sent to /elgato.

Get a device's current settings:

curl --location --request GET 'http:https://192.168.1.61:9123/elgato/lights' --header 'Accept: application/json'

Key Light devices do not require authentication.

Key Light devices only return two HTTP status codes:

• 200 OK The request has succeeded.
• 400 Bad Request The request was not understood by the device (likely because of malformed syntax)

Additionally, any data returned by a device will be JSON-formatted.

There are only three resources implemented by the Key Light API

• lights lights objects contain information related to a Key Light device's current state, brighness, and color temperature
• accessory-info accessory-info objects contain information related to a Key Light device's physical hardware specifications
• settings settings objects contain information related to a Key Light device's behavior

There is one 'action' implemented by the Key Light API:

• identify sending a HTTP POST requst to this endpoint will cause the given light to flash a few times