The Extended Feedback Page (EFP) offers several advanced parameters that let you pass information between your email platform, FeedLetter surveys, and your own website or app. These optional parameters help you personalize feedback flows, track responses, and capture reader data such as email addresses for post-survey actions or integrations.

Below are the available features and how to use them.

Passthrough Parameter

You can append a passthrough parameter to your survey voting URL to forward a custom value to the Thank You Redirect URL.

This is useful for keeping track of identifiers such as campaign IDs, user IDs, or any custom metadata.

Example:

https://a.feedletter.co/s/<survey-id>/1?passthrough=my-custom-value

When the survey completes, this value will be automatically passed to your redirect link in the query parameter passthrough.

✅ Available for: Newsletter Surveys and One-Time Polls

Adding the Reader’s Email Address to the Survey Links

If you want to prefill the reader’s email address, you can:

1. Use your ESP’s Merge Tag system with the preselector provided under Survey Details → Code, or
2. Append the e query parameter manually.

Example:

https://a.feedletter.co/s/<survey-id>/1?e=john.doe@example.com

If Advanced → “Prefill Email Address If in Request” is enabled, the email address will be prefilled on the EFP when the reader opens the survey.

If this option is not enabled, the email address will only be routed through to the redirect URL (it won’t appear in the EFP input field).

🕊️ Note: The email is not automatically assigned to the vote or comment. Feedback remains anonymous unless the reader enters their email manually or leaves the prefilled one intact—in which case it is then associated with their comment.

✅ Available for: Newsletter Surveys and One-Time Polls

Retrieve the Reader’s Email Address in the Thank You Redirect

You can include the reader’s email in your Thank You Redirect URL to receive it on your website or backend for follow-up actions (e.g. tagging in CRM, analytics tracking, etc.).

1. Go to Survey Details → Customize → Thank You Page
2. In the Redirect field, use {email} as a placeholder in your URL.

Example:

https://example.com/my-redirect-page?email={email}

The placeholder {email} will be replaced with the reader’s actual email address if it was prefilled via Merge Tag or entered manually.

✅ Available for: Newsletter Surveys and One-Time Polls