How to see the behavior of users on a website?

Try Intercom.io You get visitor level information on how active they are etc.

Sorry to be a bit blunt in my answer, but the client hired your "e-commerce web agency" to do e-commerce conversion optimization, yet your company doesn't know how to do e-commerce conversion optimization? Perhaps have a conversation with someone in your company or talk to your manager or the agency principal and encourage them to hire for e-commerce conversion optimization expertise. It's an entire discipline requiring years of experience and track record in driving higher conversions for e-commerce sites (in my opinion). In lieu of that, how many marketing dollars are going to be spent to drive traffic to the site and who is managing that part? Often new start-ups will spend so much of their dollars BUILDING the site, they don't leave much money to spend on AdWords or other methods to drive traffic to it. The amount of traffic will help determine how many tests to run and how often. Usually we start with two very different landing pages (do you have landing pages?), then fine-tune the split testing down to things like headlines and photos. The checkout pages, especially any pricing pages, are also critical in the testing. Is it a brand new concept or established product/service? If brand new, it will take very well-crafted pages to get visitors to pay money for something (vs. a trial). If established, why is your product best and why should I buy now? You should map out the conversion flows to the confirmation page (success page) and measure the drop-off or conversion rates at each step. Test different elements/pages at each step. Also measure things like average cart size (if more than one product), revenue per transaction and long-term customer value. Hope that helps. Best wishes to you!

NO, there no current tools available.

I have been managing multiple domains/sites for my clients since a few years now and I think the easiest and best way to do it in your case would be setting up simple WordPress sites on each one of them and managing them with something like ManageWP(https://managewp.com/) . If they're niche domains, you can monetize them through ads or use them as affiliate sites. Selling them can also be also an option. If you can get the sites to look fairly nice and if they are niche domains, you can sell them on sites like Flippa(https://flippa.com/) . Overall, you have many options. I'd be glad to help you in detail through a call if you want.

Much, if not all, of what you are looking for can be accomplished in Google Analytics using their Conversion Goals. I am not sure about *all* of it - specifically the information you want the merchants to have access to. There are tools that do analytics better and more detailed for applications like this, but GA is the best for your price point. You will want to plan for growth and moving to a more comprehensive solution, as your web app grows. Questions, comments, concerns, gripes, compliments or complaints? Book a call.