title: Is Google Firestore get() request for a non existing document, charged?
body: <p>I recently realized that even if a Firestore <code>query</code> doesn't match any document, I will still be charged for 1 read.</p>
  
  <p>In my case, there could be lots of queries for non-existing docs, and I want to avoid this cost. </p>
  
  <p>In my case, the client already has (or can generate locally) the relevant <code>document Id</code> beforehand, but the client still doesn't know if this document exists or not. 
  So instead of querying and receiving the doc, I can do <code>get(docId)</code></p>
  
  <p><strong>Question</strong>: Does the Firestore charge for replying <code>error</code> to a <code>get()</code> request of the non-existing document?</p>