URL prefilling allows you to automatically populate form fields when users visit your RSVP pages by including data in the URL parameters. This is particularly
useful for email marketing campaigns where you want to reduce friction and improve user experience.
Built-in RSVP Field Prefilling
Name and Email Fields
The name and email fields in your RSVP forms can be automatically populated using these URL parameters:
rsvp_name- Prefills the name fieldrsvp_email- Prefills the email field
Examples
Basic Usage:
https://addcal.co/e/your-event?rsvp_name=John%20Doe&[email protected]
Mailchimp Integration:
https://addcal.co/e/your-event?rsvp_name=*|FNAME|* *|LNAME|*&rsvp_email=*|EMAIL|*
Other Email Marketing Platforms:
Klaviyo:
?rsvp_name={{ person.first_name }} {{ person.last_name }}&rsvp_email={{ person.email }}ConvertKit:
?rsvp_name={{ subscriber.first_name }} {{ subscriber.last_name }}&rsvp_email={{ subscriber.email_address }}ActiveCampaign:
?rsvp_name=%FIRSTNAME% %LASTNAME%&rsvp_email=%EMAIL%
Custom Query String Fields
For more advanced use cases, you can create custom fields that automatically populate from URL parameters.
Query String Fields
Field Type: query_string
Visible to users on the form
Auto-fills from a specified URL parameter
Users can see and modify the prefilled value
Field Type: query_string_hidden
Hidden from users (not visible on the form)
Auto-fills from a specified URL parameter
Useful for tracking data like UTM parameters, referral codes, etc.
Configuration
When creating a query string field:
Field Type: Select “Query String” or “Query String (Hidden)”
Label: What users see (for visible fields only)
Query Parameter Name: The URL parameter to extract data from
Examples
UTM Source Tracking:
Field Type: Query String (Hidden)
Query Parameter Name:
utm_sourceURL:
?utm_source=newsletterResult: Field captures “newsletter” without showing it to the user
Referral Code:
Field Type: Query String
Label: “Referral Code”
Query Parameter Name:
refURL:
?ref=FRIEND2024Result: Shows “Referral Code” field prefilled with “FRIEND2024”
Campaign Tracking:
Field Type: Query String (Hidden)
Query Parameter Name:
campaign_idURL:
?campaign_id=summer2024Result: Captures campaign data for internal tracking
Best Practices
URL Encoding
Always URL encode your parameters:
Spaces become
%20Special characters are encoded appropriately
Most email marketing platforms handle this automatically
Email Marketing Integration
Test your links before sending to your full list
Use fallback values in your email templates
Consider mobile users - shorter URLs work better
Track effectiveness using hidden query string fields
Technical Details
Processing Order
Built-in parameters (
rsvp_name,rsvp_email) are processed firstCustom query string fields are processed next
Only empty fields are prefilled - existing data is never overwritten
Form Compatibility
Works with all custom RSVP forms
Compatible with default and custom appearances
Functions alongside all other form field types