title: API, back-end and front-end as all three separate components
body: <p>I tried to find something on the internet but could not find anything similar. So I'm asking it here:</p>
  
  <p><strong>SITUATION:</strong>  I have a big API which does some heavy calculations and has a lot of functionality. There are some clients using this API and has implemented it in their software. Now I want to write some front-end for that API so some users could manage their workflow more easily. </p>
  
  <p><strong>CONSIDERED SOLUTION:</strong> I am considering of making a separate back-end application which would use an API and serve for the front end (look at the picture attached). The backend would do authorization / caching / data-adapting operations.</p>
  
  <p><a href="https://i.stack.imgur.com/zHFUd.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/zHFUd.png" alt=""></a></p>
  
  <p><strong>QUESTION:</strong> But I have never ever crossed such app design with three layers API-BE-FE. So is it worth making things this way? Are there any significant drawbacks? Is it safe to put some oauth authorisation in the back-end side, not api itself? Like what are your thoughts about it?</p>