Since Zigbee is in the 2.4 GHz band, will it interfere with my WiFi (or vice versa)?

Zigbee was developed in the era of ubiquitous WiFi, and so was designed specifically to coexist in noisy 2.4GHz environments. This includes the ability of Zigbee radios to time their transmissions "in between" wifi transmissions, and to rapidly repeat messages (easier to do with low-bandwidth networks). Zigbee's mesh network technology also allows networks to route data through the path of least interference.

So it is very rare for users to experience interference issues between Zigbee devices and WiFi devices, even under some of the most extreme conditions.

However, one thing to consider is that if both types of radios are included in the same device (e.g. a gateway with a WiFi module and a Zigbee module), it is important to follow some best practices to ensure optimal performance. We can talk to you about your application and help you implement your hardware and software solution to minimize any coexistence issues. Silicon vendors also commonly offer best practices and support for coexistence. Silicon Labs provides some excellent guidance here.