Skip to main content

Pre-filling Forms with URL Parameters

Simplify your supporters’ experience by automatically filling form fields with known information using URL parameters.

Written by Clare Atreo

What is it?

You can pre-fill form fields by adding parameters to your form’s URL.
This feature works with:

  • Petitions

  • Online forms

  • Action sign-up forms

It helps you save time and improve form completion by pre-filling data you already know about your contacts (e.g., from your CRM).

⚙️ How It Works

Add parameters to the end of your form URL in the following format:

?parameter=value

To combine multiple fields, separate them with &.

Start from your page’s link on your Action Hub (your-organization.qomon.org or your own domain), for example https://your-organization.qomon.org/en/petition/1a2b3c4d-save-our-park/. Keep the language part of the link (/en/, /fr/…). Without it, the page redirects to its language version and the pre-filled values are lost.

Example:

https://your-organization.qomon.org/en/online-form/1a2b3c4d-your-form/?firstname=John&[email protected]

When the user clicks this link:

🧩 Standard Fields

Here are the fields you can pre-fill with URL parameters:

Personal Information

Field

Accepted Parameters

Example

First Name

firstname, first_name

?firstname=John

Last Name

surname, lastname, last_name

?lastname=Smith

Email

mail, email

[email protected]

Mobile

mobile, phone_mobile

?mobile=%2B33612345678

Landline

phone, telephone

?phone=%2B33123456789

Birth Date

birthdate, date_of_birth

?birthdate=1990-05-15

Birth City

birthcity, birth_city

?birthcity=Paris

Birth Country

birthcountry, birth_country

?birthcountry=France

Nationality

nationality

?nationality=French

Gender

gender, sex

?gender=male

Address Details

Field

Accepted Parameters

Example

Building

building

?building=Tower%20A

Floor

floor

?floor=3

Door

door

?door=12B

Street Number

housenumber, house_number

?house_number=42

Street Name

street

?street=Main%20Street

Address Addition

addition

?addition=Apt%204

Postal Code

postalcode, zipcode, zip

?postalcode=75001

City

city, town

?city=Paris

State/Province

state, province

?state=California

County

county

?county=Kings

Country

country

?country=France

🛠 Custom Fields

If your form has custom fields, you can pre-fill them using their field ID (contact support via the live chat to find your ID):

?custom_12345=MyValue

or

?custom:12345=MyValue

💡 Practical Examples

Example 1 – Petition

https://your-organization.qomon.org/en/petition/1a2b3c4d-save-our-park/?firstname=Sarah&[email protected]&postalcode=75001

Example 2 – Event Sign-up

https://your-organization.qomon.org/en/action/1a2b3c4d-rally/?firstname=Michael&surname=Johnson&[email protected]&mobile=%2B33698765432&city=Lyon

Example 3 – Multiple Values

For checkbox custom fields, separate the options with commas. Use each option’s value or label exactly as it appears in the form.

https://your-organization.qomon.org/en/online-form/1a2b3c4d-volunteer-form/?custom_12345=canvassing,phonebanking,events

Example 4 – Full Example

https://your-organization.qomon.org/en/online-form/1a2b3c4d-membership/?firstname=Emily&surname=Brown&[email protected]&mobile=%2B33612345678&street=45%20Rue%20de%20la%20Paix&postalcode=69002&city=Lyon&country=France&custom_789=Premium

⚠️ Notes & Best Practices

Special Characters

  • Use %20 or + for spaces → Rue%20de%20la%20Paix

  • Write a + as %2B, otherwise it becomes a space. This matters for phone numbers → %2B33612345678

  • @ can be written as %40 or just @

  • Accented characters are supported but can be encoded (é → %C3%A9)

Best Practices

  1. Encode URLs properly for special characters.

  2. Respect privacy when sharing links containing personal data.

  3. Test your pre-filled links before sharing.

  4. Fields remain optional – users can edit or remove pre-filled values.

  5. Case-insensitive – ?FirstName=John works like ?firstname=John.

What Happens If...

Situation

Behavior

Parameter doesn’t match a field

Ignored

Field already filled

Overwritten by URL value

Multiple parameters for same field

Last one applies

Empty parameter (?firstname=)

Ignored

💬 Need Help?

If you need help setting up pre-filled forms or identifying custom field IDs, contact your account manager or our support team at [email protected].

Related Articles
Did this answer your question?