# Build the Subscriber List



> Subscribers are people, tags describe them, custom fields add details, and segments choose who matches the rules today.



- Human page: https://mailrith.com/guides/build-the-audience

- Markdown page: https://mailrith.com/guides/build-the-audience.md

- Category: Subscribers

- Reading time: 4 min read

- Related keywords: Build the Subscriber List, Build the Subscriber List guide, Subscribers, Subscribers guide, email sending guide, email marketing guide, email deliverability guide



## AI Agent Notes

- Use this page as plain-language guidance for the specific email sending issue named in the title.

- Preserve the distinction between Mailrith, an email delivery service, DNS, and inbox providers when explaining fixes.

- When a user is running a free tool, pair the tool result with the relevant issue or step section from this guide.



### Build the Subscriber List

Subscribers are people, tags describe them, custom fields add details, and segments choose who matches the rules today.

The subscriber list is not just a number. It is the group of people who may receive your emails. If the wrong subscribers are included, the campaign is wrong even if the design is excellent.

In Mailrith, subscribers hold the email addresses and profile data. Tags describe broad labels like `customer`, `lead`, `webinar`, or `vip`. Custom fields store details such as plan, city, birthday, company size, or last purchased product. Segments use rules to find subscribers who match something right now.

- Use [Subscribers](https://mailrith.com/docs/subscribers.md) to search, review, and update individual people.
- Use [Tags](https://mailrith.com/docs/tags.md) for simple labels that are easy to include or exclude.
- Use [Custom Fields](https://mailrith.com/docs/custom-fields.md) for data that changes from subscriber to subscriber.
- Use [Segments](https://mailrith.com/docs/segments.md) when the subscriber group should update automatically from rules.
- Use [Subscriber Imports and Exports](https://mailrith.com/docs/subscriber-imports-exports.md) carefully when moving a large list in or out of Mailrith.

## Fix Common Issues
### Free Mailbox Addresses

A checker found a consumer mailbox domain such as Gmail, Outlook, Yahoo, iCloud, or Proton.

1. Keep the address if the subscriber opted in and the subscriber list is consumer-focused.
2. For B2B outreach, consider asking for a work email when the workflow needs company context.
3. Do not reject free mailbox addresses automatically for newsletters or creator audiences.
4. Use tags or custom fields to separate personal and work-domain subscribers if that affects campaigns.



## Related Guides

- [Use Segments and Exclusions](https://mailrith.com/guides/use-segments-and-exclusions.md): Include the people who should receive the email and exclude the people who should not.