Vkontakte|Facebook how to implement a client on Node.js?

Question

JavaScript

For a long time I have been looking for the implementation of a simple client for VK and Facebook. I need DOM manipulation, to be brief on purpose. I can’t find a solution, because no one has created something like this, I need a full copy of VK-FB, correspondence, news, and so on. That is, you need to parse data in real time. The SDK does not give me a simple solution, because I want to create this client as a web service (for 1000 - 5000 people), so requests to the VK and FB servers should come from the client, and not from me as an intermediary. Right now I'm looking towards the browser simulator, but I still don't understand how to implement it. A person must go to the site, log in and have the functionality of fb and vk