Yes, you are allowed to add custom fields to your email subject lines, just make sure that you add proper place holders like [FIRST_NAME] in the email subject lines and it will be replaced after you send email newsletters.

This is why because, you are only previewing your newsletter, technically there is no other data associated with it. Hence only the placeholders get displayed, the custom fields and the unsubscribe link will show up when you send your newsletter to your contact list.

Custom fields, you might have heard this word in your senders account. Have you ever wonder what is the use of this? Or why does it have been included in the features? Collecting your subscribers email address and getting permission from them to send campaigns to their inboxes is the most essential part in email marketing. But after this, what if you want to personalize your messages. Personalization is the key factor to get engaged with your subscribers in the very best way. There comes the pa...

Whenever you create a custom field, set a default value for that if you don't want to make it a mandatory, so that it carries a default value if your contact left blank. If you set a default value as "Friend" for the custom field "First name" then if your contact does not enter their first name then it will be recorded as "Friend". While creating your email newsletter, if you set your custom field to be "Dear [FIRST_NAME]", if it is filled or left blank still you carry a name like "Dear Frien...