Need to build simple crypto payment forwarding website similar as www.blockonomics.co. Business owners will register on our website, install plugin to their website and they will be able to accept crypto payments instantly. This processor will not have FIAT currency, it should receive payments in crypto currency and will send automatically crypto currency to merchant wallet. Merchants who register on the website should see detailed transaction history. We will change 0.5% from every payment. Plugins have to be build for 5 most popular platforms such as magento, shopify, woocommerce. At start we can accept bitcoin payments only, later we will add more payment methods. Most important is security, system have to be safe to avoid hacking and stealing of crypto currency.
You can use open source code of [login to view URL], they have open source plugins too, it will made this job much easier.