title: Dealing With Mandrill Soft Bounces
body: <p>I use the Mandrill API to get the rejection list, and currently for entries where they are marked as <code>hard-bounce</code>, <code>spam</code> or <code>unsub</code> I remove them from my mailing list so that I will not attempt to send to them any more.</p>
  
  <p>However, I am not sure how to approach dealing with addresses that have been marked as <code>soft-bounce</code>.</p>
  
  <p><a href="https://mandrill.zendesk.com/hc/en-us/articles/205582937-What-happens-if-an-email-bounces-" rel="nofollow">The documentation</a> seems to indicate that these may be transient errors, and that unlike say MailChimp, soft bounces don't harden over time.</p>
  
  <blockquote>
    <p>Mandrill doesn't automatically convert soft bounces to hard bounces. If you're seeing a lot of soft bounces to an address, it may be a sign that the address is unusable.<sup><a href="https://mandrill.zendesk.com/hc/en-us/articles/205582937-What-happens-if-an-email-bounces-" rel="nofollow">1</a></sup></p>
  </blockquote>
  
  <p>How have others approached these soft bounces when trying to keep their lists high in quality? I have considered maybe keeping a count of how many days they have been there, but I have no way to know how Mandrill determine how long that they keep items on the list before attempting again.</p>
  
  <p><strong>In summary: How should soft bounces be managed by the sender to ensure high quality lists?</strong></p>
  
  <p>Here's an example of the JSON returned on one of my soft bounces that should (by looking at the obviously fake email address) be eventually removed:</p>
  
  <pre><code>{
    "reason": "soft-bounce",
    "detail": "smtp;550 \"aaa@wp.pl\": This account is disabled or not yet active (#5.1.1)",
    "last_event_at": "2015-10-06 10:16:46",
    "email": "aaa@wp.pl",
    "created_at": "2015-10-02 10:10:56",
    "expires_at": "2015-10-08 10:16:46",
    "expired": false,
    "subaccount": "XXXXXXXX"
    ,"sender": null
  }
  </code></pre>