# Custom Fields

> Mailrith Custom Fields store subscriber details for personalization, segments, forms, imports, and automation rules.

- Human page: https://mailrith.com/features/custom-fields
- Markdown page: https://mailrith.com/features/custom-fields.md
- Feature category: Send More Relevant Emails
- Primary keyword: email subscriber custom fields
- Related keywords: custom fields email marketing, subscriber data fields, email personalization fields, custom subscriber attributes
- Last reviewed: 2026-07-12

## Direct Answer
Custom Fields store subscriber details that need a specific value, not just a label.

- Store text, number, date, and yes-or-no details about subscribers.
- Use field values in forms, imports, subscriber profiles, segments, and personalization.
- Define fields clearly before a large import or email send.

## What This Feature Helps You Do
- **Better Personalization:** Fields can store subscriber details that help you write more relevant emails, such as plan, company, city, or renewal date.
- **Cleaner Imports:** Create the field before import so each CSV column has a clear destination.
- **Smarter Segments:** Segments can use field values to find subscribers who match specific conditions.

## When To Use This Feature
- You need to store a value that can be different for each subscriber.
- The value should be used for personalization, segments, forms, or automations.
- You want a clear place for each subscriber detail before you import or collect information.

## When This May Not Be The First Thing To Set Up
- A simple yes-or-no label is enough. A tag may be cleaner.
- You will never use the value for choosing subscribers, personalization, reporting, or support.
- The information is sensitive, and you do not have a clear reason or consent to store it.

## A Simple Setup Path
1. List the subscriber details you actually need.
2. Choose the right field type for each subscriber detail.
3. Create the field before you collect the value in forms or imports.
4. Use clear field names so teammates understand what each field means.
5. Review fields before major sends, then remove fields that are no longer useful.

## Common Mistakes To Avoid
- **Choosing The Wrong Field Type:** A date should use a date field, a number should use a number field, and a yes-or-no value should not be stored as free text.
- **Collecting Nice-To-Have Data:** Every field should have a clear purpose. Extra fields make forms longer and subscriber data harder to maintain.
- **Changing Meaning Later:** If a field called plan means product plan today and pricing tier tomorrow, old segments can become unreliable.

## How This Connects With The Rest Of Mailrith
- Forms and landing pages can collect custom field values.
- Segments can filter by custom fields.
- Broadcasts and sequences can personalize with field values.
- Automations can use fields in conditions.

## Keep Exploring
- [Custom Fields Guide](https://mailrith.com/docs/custom-fields.md): Create typed fields and use them across subscriber records, forms, segments, and email personalization.
- [Tags](https://mailrith.com/features/tags.md): Mailrith Tags help organize subscribers by source, interest, stage, behavior, and email sending rules.
- [Segments](https://mailrith.com/features/segments.md): Mailrith Segments creates reusable subscriber groups from tags, custom fields, status, forms, sequences, and activity rules.
- [Landing Pages](https://mailrith.com/features/landing-pages.md): Mailrith Landing Pages let you build hosted signup pages with forms, page sections, success pages, and reporting.
- [Broadcasts](https://mailrith.com/features/broadcasts.md): Mailrith Broadcasts help you write, select subscribers, test, schedule, send, and review one-time emails.

## Related Email Sending Setup Pages
- [Amazon SES Email Marketing](https://mailrith.com/features/amazon-ses-email-marketing.md): Use Mailrith with Amazon SES for email marketing campaigns, newsletters, forms, automations, and reports while Amazon SES handles delivery.
- [Postmark Email Marketing](https://mailrith.com/features/postmark-email-marketing.md): Postmark Email Marketing with Mailrith: run campaigns, newsletters, forms, automations, and reports while Postmark handles delivery.
- [SendGrid Email Marketing](https://mailrith.com/features/sendgrid-email-marketing.md): SendGrid Email Marketing with Mailrith: run campaigns, newsletters, forms, automations, and reports while SendGrid handles delivery.