Customize regular expressions (Patterns) of a form's text box

If you want a text box in a form to accept only certain values or a certain number of characters, you need to set up a regular expression (Pattern) for each question. This is a very technical topic, so don't be afraid to reach out to our support team if you have any questions.

The programming language used for patterns is Java.

In this example, we want the form to only accept letters (either uppercase or lowercase):

Simple examples:

Now, you'll see a table with commonly used regular expressions (Patterns). You can find a more complete guide here: Official regular-expression Java Patterns

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Updated on: 02/10/2026