title: Should Frontend or Backend handles currency conversions?
body: <p>I have a marketplace where people can sell their products in the currency of their home country.
  And people from all over the world can buy their products, but they are always charged in the currency of the product's seller.</p>
  <p>So if a seller in Germany sells something to someone in the UK, the UK buyer will pay it in Euros.</p>
  <p>But I want users to be able to <em>see</em> prices in their local currency, and they can choose their local currency via some interface.</p>
  <p>So my question is: who should own the currency conversion?</p>
  <p>Should the Backend only store the &quot;original&quot; price in the &quot;original&quot; currency (the one defined by the seller), and the Frontend handles the currency conversion based on user's preference?
  Or should the Backend handles the conversion and provide the price in any currency back to the Frontend?</p>
  <p>From the scalability perspective, we are currently only working with a couple of different currencies, but we plan to expand to several new ones (maybe a couple of dozen).</p>
  <p>And our products involve a website, iOS and Android native apps, and they should all work in the same way.</p>