Is it possible to use an Amazon Echo with HomeKit?
Philips Hue Bulbs are controlled by the Philips Hue Bridge or other ZigBee compatible bridge. HomeKit and Apple TV don't function as a true bridge or hub as it requires other hubs and bridges to connect to smart devices. The Apple TV simply gives you a remote connection from Apple TV to iOS over internet via iCloud.

Hue Bulb --(ZigBee)--&gt; Hue Bridge --(LAN)--&gt; HomeKit via Apple TV --(LAN/WAN)--&gt; iOS device


Now, you can't use Amazon Echo with HomeKit, but this doesn't matter. Amazon uses Hue Bridge's built-in APIs to connect to Hue. Amazon and Hue can connect regardless of your HomeKit setup.

Hue Bulb --(ZigBee)--&gt; Hue Bridge --(LAN/WAN)--&gt; Amazon Echo


You can use both HomeKit and Amazon Echo (including Dot, Plus, Spot, and Show) in conjunction with HomeKit via iOS and Apple TV, provided you have the Hue Bridge as your controller.