title: How to interact with back-end after successful auth with OAuth on front-end?
body: <p>I want to build small application. There will be some users. I don't want to make my own user system. I want to integrate my application with oauth/oauth2.0.</p>
  
  <p>There is no problem in integration of my front-end application and oauth 2.0. There are so many helpful articles, how to do this, even on stackoverflow.com. For example <a href="https://stackoverflow.com/questions/18218293/angularjs-oauth">this post</a> is very helpful.</p>
  
  <p>But. What should I do after successful authorization on front-end? Of course, I can just have flag on client, which says "okay, mate, user is authenticated", but how I should interact with my backend now? I can not just make some requests. Back-end - some application, which provides API functions. EVERYONE can access this api.</p>
  
  <p>So, I need some auth system anyway between my FE and BE. How this system should work?</p>
  
  <p>ps I have some problems with English and may be I can not just correctly 'ask google' about it. Can you provide correct question, please :) or at least give some articles about my question.</p>
  
  <h1>UPD</h1>
  
  <p>I am looking for concept. I don't want to find some solution for my current problem. I don't think it is matters which FE and BE I use (anyway I will 
  provide information about it below)</p>
  
  <p>FE and BE will use JSON for communication. FE will make requests, BE will send JSON responses. My application will have this structure (probably): </p>
  
  <ul>
  <li>Frontend - probably AngularJS</li>
  <li>Backend - probably Laravel (laravel will implement logic, also there is database in structure)</li>
  </ul>
  
  <p>Maybe "service provider" like google.com, vk.com, twitter.com etc remembers state of user? And after successful auth on FE, I can just ask about user state from BE? </p>