When using PubNub in a server application on Heroku or Google App Engine (perhaps other hosted environments), it could cause the Daily Active Devices metric (DADs) to be higher than expected. When publishing messages in these hosted environments, the IP address may change with each publish. To get an accurate daily active device count, create a UUID and set it on the PubNub instance and reuse that UUID for each subsequent publish and request, via PubNub Support, that your account be billed based on UUIDs instead of Daily Active Devices.