Following my previous question, I'm now evaluating the possibility of using a hosted platform for the ecommerce project I have to implement. Before I start "playing" with each one of them, I'd like ask if anybody knows which ones allow a good degree of customization.
At the moment I'm looking at BigCommerce, but it seems that customization is limited to templates, while I need additional features which require PHP Coding. Also, I'd need to be able to import additional product data into the system, and I'd need to do this via code; I had a look at some integrations, but they gave me the impression that they all run on the rendered page via JavaScript. For example, if I want to show Facebook Reviews on a product, I'll have to add some JS that will fetch it and show it on the page. This is not optimal, as I must cater for people with JS disabled, therefore I'd need to run my own PHP code.
Update
As suggested, I'd like to explain that "customization", in my case, means altering or extending the normal ecommerce workflow by "tapping" into events and performing specific operations (in my case, I'd have to add a handler of a hypotetical "AfterPurchaseComplete" event). This can't be achieved in a system that just allows to add JavaScript (which, as I wrote above, can be disabled and, therefore, useless), as it has to be executed by the server itself, in the same way many framework's run plugins. I could understand that hosted solutions don't normally allow arbitrary code to run on their systems, but, unfortunately, this would preclude all chances of using them.