Custom fields - Railmail

Custom fields let you store your own attributes on subscribers, then use them in segments, campaigns and automations.

Create a custom field

In Custom fields, open the field builder, pick a type, and configure its properties:

Property	Notes
Display name	The human-readable label.
Field key	Used in placeholders as `{{custom.<key>}}`. Lowercase letters, digits and underscores only.
Description	Optional explanation.
Default value	Optional value used when none is set.
Required when editing subscribers	Makes the field mandatory in the subscriber form.
Options	For Single choice and Multiple choice fields.

You can also set validation: min/max length, a regex pattern, min/max value or step, depending on the type.

Type	Use for
Text / Long text	Short or multi-line text.
Number / Decimal	Whole or fractional numbers.
Date / Date & time	Dates, with or without a time.
Yes/No	Boolean values.
Single choice	Pick one option from a list.
Multiple choice	Pick several options.
URL / Email / Phone	Validated formats.
Computed	A value derived from other fields via a logic editor.

Reference a field in email content and merge tags with its key:

Hi {{custom.first_name}}, your plan is {{custom.subscription_tier}}.

Unknown or misspelled placeholders are flagged by the campaign pre-send analysis and can block a send. Double-check field keys.

Scope: fields are either System (built in) or User-defined (created by you).
Status: Active or Archived. Archive a field to retire it without deleting data; you can unarchive or delete it later.