Custom fields for contacts

Custom fields store additional data on each contact — company, location, subscription tier, birthday, or anything else worth knowing about your audience — beyond Letterhead’s built-in profile fields. Use those values to build segments and personalize newsletter content with personalization tags.

How custom field values get filled

• Signup forms — answers readers provide in extra fields when subscribing through your signup form save directly to their contact record. See Save signup form responses to contact records.
• CSV import — if your CSV includes columns matching existing custom field names, Letterhead populates those values automatically during import. You can’t create new fields via import.
• API and Zapier — update field values programmatically through the Zapier integration or the Letterhead API.
• Manually — edit values on any contact from their profile.

You can create custom fields for your account yourself — for example, a field to store a subscriber’s birthday. From your Audience page, open the Settings tab, find Custom Fields, and click Add field to name it and choose its type.

Use custom fields in segments

Custom fields appear as conditions when you create or edit a segment — for example, city equals New York — and can be combined with tags using ANY/ALL logic.

Use custom fields in email content

Reference a field in your newsletter with a personalization tag, optionally with a default value for contacts missing the field.

When a value looks like sensitive information

Some data doesn’t belong in a contact record. Letterhead replaces custom field values that look like payment card numbers, US social security numbers, or similar sensitive details with a clear placeholder — so a field that held a card number will read something like “[REDACTED: possible credit card number]” the next time you open that contact. That applies whether the value came through a signup form, the API, Zapier, a CSV import, a connected tool, or was entered by hand, and anything already stored is cleaned up overnight.

A few things worth knowing if you come across one:

• The original value isn’t kept anywhere. That’s the point: it’s removed so it isn’t stored, rather than hidden. Letterhead can tell you which field was cleared, when, and what kind of information it looked like — but not what it said.
• It can’t be undone. If the value was something you still need, re-enter it. You’ll have it already, since the information came from you.
• Occasionally it catches something innocent. A long order number or tracking number can happen to look like a card number. If that keeps happening on a field, it’s worth a word with support.

If a value was cleared and you’re not sure why, support can look up which of that contact’s fields were affected and when.

Reserved system fields

Letterhead maintains read-only system fields prefixed __lh. — such as the subscriber’s mailbox provider and engagement state. You can segment on these fields but can’t edit or delete them.

Related

• What are audience profile fields? — the full list of built-in fields.
• Working in Audience