MailerPress doesn’t send a campaign to all your contacts at once. It splits the recipients into batches (small groups of emails) and sends one batch at regular intervals, with a limit on emails per second. The sending frequency settings control this pace. Sending too fast can overload your server or exceed your sending service’s limits, which hurts deliverability (your chances of reaching the inbox). Sending too slowly delays your campaigns.
Open the sending frequency settings
Go to MailerPress > Settings > Sending frequency, or click Adjust sending frequency on your primary provider’s card in MailerPress > Integrations.
The first card shows your Active email service provider (your primary provider) with a note, such as a deliverability warning for PHP Mail or Gmail’s daily limits. Click Change provider to choose another service. Profiles depend on this provider, so configure your sending service first (see Choose and configure your email sending service).
Below, Current Configuration sums up the settings in use: Batch Size (emails per batch and interval), Emails per Hour, Emails per Day and Rate Limit (maximum emails per second within a batch).
Choose a configuration mode
Under Configuration Mode, pick one of three options, then click Save settings.
Automatic
MailerPress picks a profile based on your email service provider and your server capabilities. This is the recommended mode for most users. The profile in use appears under Currently using.
Profile
Pick a ready-made profile in the Profile list to match your plan with your sending service (see below). The recommended profile is marked with a star. MailerPress shows its description and its throughput Per Hour and Per Day.
Manual
Set your own values. This mode is for advanced users: wrong values can cause delivery issues or overload your server.
| Setting | Description |
|---|---|
| Emails per chunk | Emails sent in each batch, from 1 to 500. |
| Interval between chunks | Wait before the next batch: 1, 2, 3, 5, 10, 15 or 30 minutes. Below 3 minutes, MailerPress shows a warning: shorter intervals may overload Action Scheduler (the WordPress task queue that sends the batches) and your server. |
| Rate limit (emails per second) | Maximum emails sent per second within a batch, from 0 to 100. 0 removes the limit (not recommended). With PHP Mail, MailerPress shows an error above 50 emails per second. |
Check the delivery time estimates
Delivery Time Estimates shows how long a campaign takes with the current settings: for 1,000 contacts (in minutes), and for 10,000 and 50,000 contacts (in hours). For example, at 75 emails every 5 minutes (900 per hour), 10,000 contacts take about 11 hours. The actual time depends on your server.
Available profiles
Each profile sets a batch size, an interval and a rate limit. The recommended profile of each service is also the default in Profile mode. PHP Mail and Custom SMTP are available in MailerPress (free); all the other services require MailerPress Pro.
| Service | Profile | Settings | Emails per hour |
|---|---|---|---|
| PHP Mail | Micro (Shared hosting – very limited) | 10 emails every 10 minutes, 1/s | 60 |
| PHP Mail | Prudent (Recommended for shared hosting) (recommended) | 25 emails every 10 minutes, 2/s | 150 |
| PHP Mail | Standard (VPS only – risky) | 50 emails every 10 minutes, 3/s | 300 |
| WordPress Default | Conservative (safe for most SMTP plugins) (recommended) | 25 emails every 10 minutes, 2/s | 150 |
| WordPress Default | Standard | 100 emails every 10 minutes, 5/s | 600 |
| WordPress Default | Performance (dedicated SMTP provider) | 250 emails every 10 minutes, 10/s | 1,500 |
| Custom SMTP | Conservative (Gmail SMTP, free providers) | 25 emails every 5 minutes, 3/s | 300 |
| Custom SMTP | Balanced (Recommended – Most SMTP servers) (recommended) | 50 emails every 5 minutes, 8/s | 600 |
| Custom SMTP | Performance (Dedicated SMTP servers) | 100 emails every 3 minutes, 15/s | 2,000 |
| Gmail | Free Gmail (500/day limit) (recommended) | 20 emails every 10 minutes, 2/s | 120 |
| Gmail | Google Workspace (2,000/day limit) | 50 emails every 10 minutes, 5/s | 300 |
| Brevo | Prudent (Free plan – 300 emails/day) | 50 emails every 5 minutes, 10/s | 600 |
| Brevo | Balanced (Recommended) (recommended) | 75 emails every 5 minutes, 15/s | 900 |
| Brevo | Performance (Premium plans) | 200 emails every 5 minutes, 30/s | 2,400 |
| SendGrid | Balanced (Recommended) (recommended) | 75 emails every 5 minutes, 15/s | 900 |
| SendGrid | Performance (Pro plans) | 200 emails every 3 minutes, 50/s | 4,000 |
| SendGrid | High Performance (Premier plans) | 300 emails every 5 minutes, 50/s | 3,600 |
| Amazon SES | Prudent (Sandbox/New accounts) | 50 emails every 5 minutes, 10/s | 600 |
| Amazon SES | Balanced (Recommended) (recommended) | 75 emails every 5 minutes, 12/s | 900 |
| Amazon SES | Performance (High volume) | 150 emails every 5 minutes, 14/s | 1,800 |
| Amazon SES | Maximum (Enterprise – AWS approved increased limits) | 200 emails every 5 minutes, 20/s | 2,400 |
| Mailgun | Balanced (Recommended) (recommended) | 75 emails every 5 minutes, 15/s | 900 |
| Mailgun | Performance (Foundation+ plans) | 200 emails every 3 minutes, 40/s | 4,000 |
| Mailgun | High Performance (Scale plans) | 300 emails every 5 minutes, 50/s | 3,600 |
| Mailjet | Prudent (Free plan – 6k/month) | 50 emails every 5 minutes, 10/s | 600 |
| Mailjet | Balanced (Recommended) (recommended) | 75 emails every 5 minutes, 15/s | 900 |
| Mailjet | Performance (Premium plans) | 200 emails every 5 minutes, 30/s | 2,400 |
| PostMark | Prudent (10k plan) | 50 emails every 5 minutes, 10/s | 600 |
| PostMark | Balanced (Recommended) (recommended) | 75 emails every 5 minutes, 15/s | 900 |
| PostMark | Performance (100k+ plans) | 200 emails every 5 minutes, 30/s | 2,400 |
| Resend | Prudent (Free plan – 100/day) | 50 emails every 5 minutes, 10/s | 600 |
| Resend | Balanced (Recommended) (recommended) | 75 emails every 5 minutes, 15/s | 900 |
| Resend | Performance (Pro plans) | 200 emails every 5 minutes, 30/s | 2,400 |
| SMTP2GO | Prudent (Free plan – 1k/month) | 50 emails every 5 minutes, 8/s | 600 |
| SMTP2GO | Balanced (Recommended) (recommended) | 100 emails every 2 minutes, 10/s | 3,000 |
| SMTP2GO | Performance (Professional plans) | 200 emails every 2 minutes, 20/s | 6,000 |
| Emailit | Prudent (Starter plans) | 50 emails every 5 minutes, 5/s | 600 |
| Emailit | Balanced (Recommended) (recommended) | 100 emails every 2 minutes, 10/s | 3,000 |
| Emailit | Performance (High volume plans) | 150 emails every 2 minutes, 15/s | 4,500 |
| ToSend | Prudent (Starter plan) | 50 emails every 5 minutes, 10/s | 600 |
| ToSend | Balanced (Recommended) (recommended) | 100 emails every 5 minutes, 20/s | 1,200 |
| ToSend | Performance (Pro plans) | 250 emails every 5 minutes, 40/s | 3,000 |
Postal has no predefined profile: use the Manual mode.
The emails per day shown by MailerPress are a theoretical maximum (emails per hour × 24). Your plan’s daily or monthly quota with the sending service still applies.
Good practices
- After changing your primary provider, open MailerPress > Settings > Sending frequency. MailerPress switches to the Automatic mode for the new provider. Check the result, change the mode if needed and click Save settings.
- On shared hosting with PHP Mail, keep a cautious profile: hosts often limit emails per hour, and going over can get your server flagged for spam.
- If batches go out late or irregularly, your site may not get enough visits to trigger WordPress scheduled tasks. Set up a real cron job (a task your server runs on a fixed schedule): see How to set up a WordPress cron job from your server.