Site speed
In 2012 an engineering team dedicated to improving website speed for Walmart discovered if an ecommerce website does not load in one second or less it starts negatively impacting conversion rates. Thus, when developing an ecommerce website this is our number one priority on the list. Achieving the desired website speed requires multiple levels of optimization. We make sure this is done properly as a slow ecommerce website is not really a good thing to have. And yes, we do not use WordPress/WooCommerce to build ecommerce websites.
Responsive design
Most traffic on ecommerce websites originate from mobiles and tabs. Thus it is very important for us to make sure that mobile visitors get the best experience on their device. Not just for the product pages but the entire checkout process. Either way, the goal is to make sure we can deliver a consistent shopping experience whether your site is accessed on a desktop or a mobile device.
Security
Well this is the third most important aspect of ecommerce development that we take care of. While this point is difficult to explain in a few words, the main story is if your ecommerce store is hosted on a single layer, you are probably sleeping on a bed of dynamite. We use multiple layers of security to fortify the ecommerce store and the main being serataing the user and admin layers completely. There are also other factors like using proper SSL certificates, proper methods of authentication including 2FA, OTP based authentication etc.