Its possible to validate your US Postcodes using a regular expression.

Step-by-Step Instructions:

Step 1: Drag and drop an question node onto the canvas. Specify the type as “text”

Step 2: Under “Advanced Options” select “Regex”

Copy and paste this regular expression:


Step 4: Under preview you can test by entering a US post code

Step 5: To the right you will see either a red failure or green success icon under “Validation”