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Custom Mailing List Fields

If your BookFunnel account is integrated with your mailing list, you can send extra data along with the reader’s name and email address when they subscribe.

Examples of additional data:

  • The title of the book they received
  • Which marketing effort brought them in (Example: Facebook Video Ad)
  • Who added them to your list (Example: Source: BookFunnel)

How To Use Custom Mailing List Fields

To send subscriber data in a custom field, you must first have created the field on your mailing list service. BookFunnel cannot create a new field for you. If the field already exists, we will send the data along with the subscriber’s email address and the custom field will be populated with the value you set.

Automatic Custom Fields

When a new subscriber’s email address is added to your integrated mailing list, additional data is always included with their email address. If your email list supports the custom field data, it will be added to the subscriber’s user profile. If your list does not have a corresponding custom field, this additional data is “thrown out” by your mailing list provider.

This is the custom data we automatically include when adding a new subscriber:

  • Country – their location at the time they subscribed
  • Country Code – a two-letter country abbreviation
  • Is EU country? – a yes or no

If you want this data to be saved to your mailing list, you will need to add one or more of these custom fields to your mailing list and name them exactly:

  • country
  • country_code OR country_cd*
  • is_eu_country OR eu_country*

*MailChimp has a character limit, so we have a short, MailChimp-friendly custom field label and a longer, more descriptive field label that you can use for every other mailing list provider.

How to Create a Custom Field on Your Mailing List




Constant Contact – Some restrictions, see Constant Contact section below




SendFox – SendFox does not support custom fields


Add custom field to your email opt-in page:

  1. Create a new email signup page or edit an existing email signup page
  2. Make sure the opt-in settings either require a reader to join your list, or invites a reader to join your list
  3. Select your list in the Integration List drop-down menu when completing the form
  4. Scroll to the bottom of the landing page form and click Advanced Settings
  5. Check “Send custom fields when adding subscribers to my mailing list”
  6. Add the name of the custom field (this is the name your mailing list provider calls the field, which may be something like MMERGE7)
  7. Add the value next to the custom field (this is the data BookFunnel will pass along with the subscriber’s email and it can be the book title, promotion name, or even a variable like {{date_time}}. Learn more about variables.)
  8. Click Save and Close

Constant Contact Custom Fields

Constant Contact has some limitations when sending custom field data through the API (the API is how BookFunnel sends data to your Constant Contact account). While you can create custom field names on your Constant Contact dashboard, their API does not allow custom field names.

What does this mean for you? It means that BookFunnel can pass along custom data, but the field name must meet Constant Contact’s API requirements. So, you can’t call the field name “book title”. Instead, you will call the field name “custom_field_8” (the number can be any number between 1-15).

Example: You want to send the book title when BookFunnel adds new email addresses to your list. First, you will create a field name in Constant Contact that their API will accept. Second, you’ll add that field name to the advanced settings panel on the BookFunnel email signup page.

Constant Contact’s Dashboard

Field type: Text

Field Name: custom_field_12 (You must use this structured “custom_field_#” as the field name, not a personalized field name. Constant Contact’s API will not accept any field name other than “custom_field_#)

Advanced Settings on BookFunnel Email Signup Page

Name: custom_field_12

Value: Wuthering Heights

When a new subscriber signs up through your opt-in landing page, BookFunnel will add their email address and “Wuthering Heights” to the field name custom_field_12.


Why isn't my data showing up?

The field must exist on your mailing list before we send the value. If the field does not exist, or the field name added to your email signup page does not exactly match the field name on your list, your list provider will not add the additional data to the subscriber. Verify that the field names match and that your list provider isn’t using an alternate field name like MMERGE7 or .

I checked the box to send custom fields and now it says “Source”. Can I delete “Source” and add something else?

You can delete the Source field or edit it to match the fields you have already created on your mailing list.

How do I find the name of my MailChimp field?

MailChimp allows you to set the “Field label,” but the merge tag is usually something like MMERGE9. The merge tag (not the field label) should be used on the BookFunnel email signup page.

To find the name of the merge tag, view your list on your MailChimp dashboard. Click Settings and then select “List fields and *|MERGE|* tags”

Locate the field label and then find the tag on the right. The tag should be copied and pasted into the BookFunnel email signup form under Advanced Settings.

Can I collect custom reader data like their birthday or favorite dessert?

This feature does not allow you to create new form fields. BookFunnel will only request the reader’s email address, and optionally their first and/or last name. These custom fields can be used to pass “secret fields”, which can be used for tracking purposes or segmenting subscribers.

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