Express Server posting user data to Craft First of all let me just say that I have only been using Craft for a few months and still has allot to learn about it.

My issue is quite simple in that I have an express server running to display the data on the front-end. I am using Craft as a solution for the client to add or change content on their site. This is working well. I am even able to use your Element API to retrieve data from Craft and together with my Express server I can manipulate and display content where it is needed. 

My client has now recently asked me to add a section that would allow users to register users and this is where I am starting to have problems. Or at least, this is where I need some expert knowledge.

I would just like to save the user data via post. I have looked at a few options out there but honestly I don't want to build a plugin to handle this. Is there a way I could post and save data to Craft without it being too complicated?
You'd normally use a front-end form to create users on a Craft site. You can add fields to this form to submit more than the standard set of fields. I believe you could use the same form within your Express app. You are just sending the data via a POST request.

Check the documentation for an example.