Custom contact fields

Contacts & Mailingcontacts3 min read

Available on Professional and Unlimited plans

Define your own fields beyond the built-in ones (email, name, company, phone, etc.) and target them in segment rules and mailing personalization.

Field types

Type	Editor control	Use for
Text	single-line input	one-off labels (job code, role)
Number	numeric input	revenue, score, account size
Date	date picker	renewal date, anniversary
Yes/No	dropdown (true/false/empty)	flags
URL	URL input with validation	LinkedIn, GitHub, blog
Email	email input with validation	secondary email
Select-from-list	dropdown with CSV options	tier (Gold/Silver/Bronze), event source

Go to Contacts → Custom fields (/contacts/custom-fields).

Click Add field.
Fill in:
- Name — must be unique within your account / org
- Type — picks the editor control above
- Options (only for Select) — comma-separated list of dropdown values
- Required — when on, contact-edit blocks save until the field is filled
- Sort order — positions the field among others on the contact editor
Save. The field appears immediately on every contact's edit page under a Custom fields card.

Open any contact (/contacts/{id}/edit). The Custom fields card auto-renders the right control for each definition:

Empty value = unset (the row in ContactCustomFieldValue is deleted, not stored as empty string).
This matters for segments: customField:Tier isSet matches only contacts with a value; isNotSet matches the rest.

In the segment rule builder, the Field dropdown lists every custom field under a Custom fields group. Operators per type:

Text / URL / Email / Select / Number / Date — equals, contains, isSet, isNotSet
Yes/No — equals true, equals false

Goal: measure which event delivered the best leads.

/contacts/custom-fields → Add field.
Type: Select-from-list. Name: Source Event. Options: 2026-Berlin, 2026-Paris, 2026-Lisbon.
After each show, CSV-import the badge scans (the field auto-renders as a dropdown on every contact).
Six months later, build a segment: Source Event equals 2026-Berlin → Run preview → 87 contacts.
Send a follow-up to that segment, compare open / click rates with the Paris and Lisbon segments.
Concrete data for next year's event budget.

Goal: keep one custom field (Tier) in sync with an external CRM.

Define the Tier select field with options Gold / Silver / Bronze.
From the CRM, push updates via POST /api/contacts/bulk with the field set per contact.
Use Tier equals Gold as a segment rule for VIP-only campaigns.
Null fields on update mean "leave existing alone", so partial syncs don't accidentally clear tiers.