title: Using Regex with Rasa
body: <p>I'm trying to use Rasa to detect entities such as phone numbers or contract ID. It seems natural to use regular expressions to define precisely those entities, and Rasa does have something called "<a href="https://nlu.rasa.com/dataformat.html#regular-expression-features" rel="noreferrer">Regular Expression Features</a>" which allows us to define regular expressions.</p>
  
  <p>Except I don't understand how to use them. In the <a href="https://nlu.rasa.com/tutorial.html" rel="noreferrer">Rasa-NLU tutorial</a>, there are regexes (like <code>"zipcode"</code>), but <strong>I don't see how they are linked to entities</strong> (<code>"location"</code>).</p>
  
  <p>Does anyone have a clue about how regexes work with Rasa ?</p>