title: how to pay through a Paypal Direct Payment if buyer have a paypal account?
body: <p><strong>Context:</strong>
  I have to implement a Ruby on Rails e-commerce website, containing a shopping cart.
  An option is to use PayPal as a payment gateway.
  The merchant (PayPal business account owner) is from Italy.</p>
  
  <p>There are two different PayPal payment workflows available:</p>
  
  <h2> 1. Express checkout:</h2>
  
  <p>in 4 steps: </p>
  
  <ol>
  <li>The web app submits a <em>payment request</em> to PayPal via some PayPal API (see below), </li>
  <li><p>The buyer is redirected to PayPal web server and once there the buyer:</p>
  
  <ul>
  <li>can login (with his paypal username and password), if they already possess a PayPal Account, or</li>
  <li>can submit credit/debit card data, if they do not possess any PayPal ACCOUNT</li>
  </ul></li>
  <li><p>confirm purchase on paypal's server, </p></li>
  <li><p>the buyer is redirected back to the application server, "where the settlement must be done to complete payment".</p></li>
  </ol>
  
  <h2>2. Direct Payment:</h2>
  
  <p>the buyer submits credit/debit card data directly into the original web app. </p>
  
  <p>I'd prefer to implement this second scenario.</p>
  
  <p>About Paypal available APIs:
  I read something here: <a href="http://paypal.github.io/" rel="nofollow">http://paypal.github.io/</a></p>
  
  <p>Paypal <em>"REST"</em> APIs are NOT still available out of the US, so I have to use Paypal "Classic" APIs.
  Using <code>gem 'paypal-sdk-merchant'</code> seems clear to me about how to submit a payment from a credit/debit card.
  I can't find any info about the possibility to submit a Direct Payment for a buyer that have a Paypal Account.</p>
  
  <p>if a buyer pays through his Paypal Account:</p>
  
  <pre><code>:payer =&gt;  {
    :payment_method =&gt;  "paypal" }
  </code></pre>
  
  <p>if a buyer pays through his credit card:</p>
  
  <pre><code>:payer =&gt; {
    :payment_method =&gt; "credit_card"}
  </code></pre>
  
  <p>So:</p>
  
  <ol>
  <li><p>Can I use the Classic API for a live Italian Merchant User?
  I'm asking because in PayPal sandbox it seems I can't set a test merchant user with country:IT ... maybe it's a sandbox limitation?</p></li>
  <li><p>Can I do a direct payment with the Classic API supplying PayPal username/password (for users who have a PayPal account) instead of creditcard data (all other users)?</p></li>
  </ol>