Blockchain exp developer with golang for crypto currency customization -- 2

Looking for a good developer or a team for 2 projects Blockchain Trading website / hyperledger /Smart Contracts, Golang to customize ethereum core : main conditions 1- fully secured 2- you should have done this type of work before 3- you should know what is bitcoin and aware of bitcoin trading 4- handle many transactions in the same time 5- I prefer if you have a ready demo or features that you can show 6- website should be easy to use 7- convert many currencies in a live time Thank you