mailpitcher

Mailbox pools, daily caps, pacing and send windows

How many emails each mailbox sends a day, how to send one campaign from several mailboxes, the four sending paces, and when emails go out.

Updated · 4 min read · 6 steps

Sending too much, too fast, gets a mailbox flagged as spam. Mailpitcher has limits that protect your mailboxes. They are on by default, and you can adjust each one.

Daily caps

Each mailbox sends at most a set number of emails a day:

  • 100 a day by default. This is what we recommend.
  • 50 a day for a new mailbox, for its first 3 days.
  • You can set 1 to 2,000. Above 100, providers often flag a mailbox. Gmail allows at most 500 a day and Google Workspace 2,000, counting everything you send.

The cap counts everything a mailbox sends in 24 hours, the emails you write yourself included. A campaign stops for the day when a mailbox reaches its cap. A single email over the cap is refused, with a message saying so.

Change a mailbox’s cap

  1. In the sidebar, click the cog next to the mailbox.
  2. Change Campaign emails per day.
  3. Click Save.

The note under it says how many this mailbox can send today. A number over 100 shows a Risk of a ban warning.

A mailbox's own settings, opened with the cog next to it in the sidebar.
  1. Sender name
  2. Campaign emails per day

See what each mailbox sent today

Open Settings, then Usage. Sending per mailbox, today shows each mailbox against its cap. The bar turns yellow near the limit, and “warm-up” marks a new mailbox.

Settings, Usage: what each mailbox has sent today against its cap.

Mailbox pools

Send one campaign from several mailboxes

In the campaign editor, under Send from, tick more than one mailbox. The campaign shares the list between them. Each still keeps to its own cap. The line under the list adds the caps up, for example Daily caps add up to 150 emails across 2 mailboxes.

A follow-up always goes from the same mailbox as the first email, in the same thread.

Send from: tick one or more mailboxes. Each sends at most its own daily cap.
  1. Tick the mailboxes to send from
  2. Their caps added up

Send windows

Choose the hours and days

Under Schedule:

  • From and Until set the hours emails may go out (09:00 to 17:00 by default). Use 5-minute steps, for example 09:00 to 09:30.
  • Time zone: your recipients’, so emails land in their working day.
  • Weekdays only: skip Saturdays and Sundays.
  • Send first emails on: Any day in the window, or Only on these dates. With dates, first emails are split evenly over the days you add, up to 3 months ahead. Follow-ups still go on any day in the window.
Schedule: the hours emails may go out, in the time zone you choose.
  1. Sending window
  2. Time zone of your recipients
  3. Any day, or only on dates you pick
  4. Weekdays only
  5. Start in the next window, or from a date

Sending pace

Pick a pace

Under Sending pace, how the emails from each mailbox are timed:

  • Steady (default): back-to-back from the start of the window, about 10 to 20 seconds apart.
  • Calm (recommended): random times across the whole window, at least 60 seconds apart per mailbox. The gentlest on your sender reputation, and the best choice for cold lists.
  • Spread out: random times across the whole window, at least 30 seconds apart per mailbox.
  • Custom: back-to-back from the start of the window, with your own gap in seconds. Under 8 seconds shows a warning: it is very likely to be flagged.

With Calm and Spread out, each day is planned up front, when you click Save & start or Resume and again at the start of every sending day. Everyone due that day gets a random time inside the window, so they all fit. A 30-minute window holds 30 emails per mailbox at Calm and 60 at Spread out, never more than the daily cap. Anyone who doesn’t fit moves to the next sending day. The campaign’s Queue shows each planned time (“at 15:12”). An email that couldn’t go at its time (the mailbox hit its cap, or the app was down) is planned again in the next window.

The box under the choices says how many fit a day, for example All 25 go out today between 15:00 and 15:30, at random times, at least 60 s apart. With sending dates, Save & start warns you when not everyone fits.

Sending pace, with an estimate of when today's emails go out.
  1. Pick a pace
  2. The estimate for your list

Set a default gap for every campaign

Don’t want to pick each time?

  • For your account: Settings, Campaign sending, tick Use a custom default, then type the gap and click Save.
  • For one project: open the project and click Sending speed, then tick Set a default for this project.

A campaign’s own pace wins over the project’s, and the project’s over the account’s.

Good to know