For LND nodes that run on Voltage, we expose the full LND API (gRPC and REST). This means you can interact with the node just like it was running on your own hardware. You can find the LND API Specification here:
To interact with your node's APIs, you must first download your macaroon. This can be found on your node's home page under the 'Admin Macaroon' tile. Simply unlock your dashboard and click 'Download'. This very similar to an API Key. It is the means by which you authenitcate to the node's APIs.