# Before You Begin: Email Limits & SMTP

Before sending large batches, it’s important to understand how email
limits and deliverability affect your setup. The plugin respects
whatever limits you define — but those limits must align with what your
provider actually allows.

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## Provider Limits

Every host or email provider enforces sending caps. Common examples:

- Shared hosts: as low as 200–500 emails per hour.
- Transactional email services (like SendGrid, Mailgun, SES): higher,
  often thousands per hour.
- Custom SMTP or Google Workspace: stricter daily quotas (e.g., 2,000
  per day).

Check your host’s documentation so you don’t risk hitting hard blocks.

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## Throttling Expectations

Mass Email Notifications lets you define:

- **Per-minute, hourly, daily, and monthly limits**.
- **Fixed resets** (e.g., midnight every day) or **rolling windows**
  (e.g., past 24 hours).
- Compound rules (e.g., 100/hour *and* 500/day).

When a limit is reached, the plugin automatically pauses a batch until
the next reset. This prevents server overload, keeps your account in
good standing, and avoids unexpected charges for going beyond your plan.

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## SMTP & Deliverability Checklist

Good settings won’t matter if emails land in spam. Improve
deliverability by:

- **Using SMTP**: Don’t rely on `wp_mail()`. Connect through a proper
  SMTP plugin.
- **Configuring authentication**: Ensure your domain has SPF, DKIM, and
  DMARC records.
- **Verifying From addresses**: Match the domain you control.
- **Testing content**: Avoid spammy subject lines, excessive links, or
  large attachments.
- **Throttling conservatively**: Even if your host allows more, slower
  pacing can reduce spam flags.

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By aligning your provider’s caps with the plugin’s throttling rules and
securing SMTP, you’ll send reliably — without interruptions or
deliverability surprises.
