A CNAME such as "hq.yourcompany.com" would be ideal. The majority of business tools that appear on Appsumo implement this. Among similar tools, I believe GoBrunch, Sessions, and 11Sight are three that implement this. This makes the experience more seamless for product users as this is meant to be integrated into an office workflow.

Additionally. I believe adding a small watermark at the bottom saying "Empowered by Cosmos" would be fine as we want your business to gain more traction too?