Data validation

Validation enforces a specific format on a text tag so that a recipient cannot submit the document unless their input matches the expected pattern. Use validation to reduce errors and avoid collecting improperly formatted data — for example, ensuring an email address looks like user@example.com before the agreement is completed.

Validation applies only to text tags. It runs in the recipient's browser at the moment they attempt to advance or complete the document.

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Built-in validation types

The following validation types are available in the Validation dropdown when you select a text tag.

Contact and identity

Type	Format enforced	Example value
EMAIL	Standard email address	jane@example.com
EMAIL_RFC5322	RFC 5322 compliant email (broadest standard)	"Jane Doe" <jane@example.com>
EMAIL_HTML5	HTML5 input[type=email] pattern (strictest)	jane@example.com
EMAIL_STRICT	Email with restricted special characters	jane.doe+tag@example.com
PHONE	Phone number (digits, spaces, dashes, parentheses)	(555) 867-5309
SSN	US Social Security Number — 9 digits, formatted or unformatted	123-45-6789
ZIP	US ZIP code — 5 digits or ZIP+4	90210 or 90210-1234

Date formats

Type	Format enforced	Example value
DATE	Any recognizable date string	March 3, 2026
DATE_MMDDYYYY	MM/DD/YYYY	03/03/2026
DATE_DDMMYYYY	DD/MM/YYYY	03/03/2026
DATE_ISO	ISO 8601 (YYYY-MM-DD)	2026-03-03

Numeric formats

Type	Format enforced	Example value
NUMBER	Any numeric value (integer or decimal)	42 or 3.14
INTEGER	Whole numbers only, no decimal point	100
DECIMAL	Number with a decimal component	9.99
CURRENCY	Monetary amount with up to two decimal places	1,250.00
PERCENTAGE	Numeric value representing a percentage	75 or 75.5
POSITIVE	Any number greater than zero	0.01

Custom pattern

Type	Format enforced	Example value
REGEX	Pattern you define as a regular expression	(depends on your pattern)

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How to apply validation

1. Select a text tag on the document canvas. The Tag properties panel opens on the right.
2. Scroll to the Validation section and open the Validation dropdown.
3. Select the validation type that matches the format you want to enforce.
4. If you select REGEX, two additional fields appear:
   • Validation pattern — enter your regular expression (without surrounding slashes).
   • Error message — enter the message recipients see when their input does not match the pattern.
5. Send or save the document. Recipients see the error message inline if they enter a value that fails validation.

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Custom regex validation

Select REGEX when none of the built-in types match your requirements. You provide the pattern and control the error message recipients see.

Writing the pattern

Enter a standard regular expression without delimiters. The engine matches against the recipient's full input, so anchor your pattern with ^ and $ if you want an exact match.

Example: To require a 6-character alphanumeric code:

• Pattern: ^[A-Za-z0-9]{6}$
• Error message: Enter a 6-character code using letters and numbers.

Common patterns with recommended error messages

Use case	Pattern	Recommended error message
6-digit numeric PIN	^\d{6}$	Enter a 6-digit PIN.
US license plate (common format)	^[A-Z]{1,3}[0-9]{1,4}[A-Z]{0,3}$	Enter a valid license plate number.
Alphanumeric order number	^[A-Z]{2}-\d{6}$	Enter your order number in the format AB-123456.
URL	^https?:\/\/.+\..+	Enter a valid URL starting with http:// or https://.
Canadian postal code	^[A-Za-z]\d[A-Za-z][ -]?\d[A-Za-z]\d$	Enter a valid Canadian postal code (e.g., K1A 0B1).
Four-digit year	`^(19	20)\d2$`

Testing your pattern

Before sending the document:

1. Use a regex testing tool such as regex101.com (select ECMAScript flavor, which matches the browser engine).
2. Paste your pattern and test it against both valid and invalid sample values.
3. Confirm the pattern rejects values you do not want to accept, not just ones you do.
4. Keep error messages specific. Tell recipients exactly what format to use, not just that the value is invalid.

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Format validation only

Validation checks that input matches the expected format — it does not verify the data is real or accurate.

For example, SSN validation confirms that 9 digits were entered in the correct pattern. It does not verify that the number belongs to a real person or matches any external record. The same applies to all built-in types: EMAIL confirms the address looks syntactically valid, but does not send a test message to confirm deliverability.

If data accuracy matters for your use case, plan a separate verification step outside of Propper Sign.