Validate field values
There are often times when it’s necessary to validate the data entered by a signer to ensure it matches a specific format. This can include phone numbers, email addresses, passport details, identification numbers, and more. DocuSeal provides the capability to choose from existing validation options for field values or create your own using regular expressions.
To do this, follow these steps:
- Click on the settings icon () located on the right side of the field within the form builder interface.
- Within the settings menu, you’ll find an option to select the validation type for the field or create your own using regular expressions.

- Select the validation type from the list or enter your custom regular expression.
- Done! Now, when the document is filled out by the signer, the entered data will be validated against the chosen format.
Available validation types
| Validation Type | Example |
|---|---|
| Length | min: 5, max: 10 |
| SSN | 123-45-6789 |
| EIN | 12-3456789 |
| support@docuseal.com | |
| URL | https://docuseal.com |
| ZIP | 60604 |
| Number only | 123456 |
| Letters only | Abcd |
Regular expressions
Regular expressions are patterns used to search and validate text to ensure it matches a specific format.
Setting up custom validation for a field is similar to selecting a validation type. Instead of choosing a predefined validation type, select Custom from the list and then enter your regular expression.

Examples of regular expressions
| Regular expression | Description | Example |
|---|---|---|
| [A-Z] | Uppercase letters only | ABCD |
| ^+[1-9]\d{1,14}$ | Phone number in international format | +1234567890 |
| ^\d{2}-\d{2}-\d{4}$ | Date in DD-MM-YYYY format | 01-01-2024 |