Warming up a mailbox, and sharing the load

Why a new mailbox starts at 20 emails a day, how it climbs, and how to split one campaign across two or three mailboxes.

Why warm up

Mail providers learn how much a mailbox normally sends. A brand-new mailbox that suddenly sends hundreds of emails in a day looks exactly like a spammer, so providers throttle it or send its mail to spam. Warm-up avoids that by starting small and growing.

How Vecta does it

Day 1 allows 20 emails.
The limit climbs a little every day.
On day 28 the mailbox reaches its own daily limit and warm-up ends by itself.

When you add a mailbox, Warm up this mailbox is ticked. Untick it for a mailbox that already sends regularly. You can switch it on or off later by editing the mailbox. The Mailboxes page shows "Warming up · day 5 of 28" and today's limit.

Your own limit still applies

Warm-up only ever lowers the limit. If your mailbox's per-day limit is 20 or less, warm-up has nothing to do and is skipped.

Example

You add a new mailbox with a limit of 300 a day and press send to 400 people. On day 1 it sends 20; the rest wait in the queue and go out as the daily limit grows. The Review step tells you this before you send.

Sharing a campaign across mailboxes

On the Schedule step, under Share the load with, tick up to two more mailboxes. The emails are divided between them in proportion to each one's daily limit, so a mailbox allowed 200 a day gets about twice as many as one allowed 100. The campaign finishes sooner and no mailbox goes over its limit.

Only mailboxes that passed their last test are offered.
Each person gets their email from one mailbox, never two.
Replies go to whichever mailbox sent the email, unless your workspace has a reply-to address set.

If something looks wrong

My mailbox only sends 20 a day: it is warming up. Check the Mailboxes page. To skip it, edit the mailbox and untick warm-up.
One mailbox finished and the campaign isn't done: each person is tied to the mailbox they were given. When that mailbox hits its limit, its share waits for the next day. Sharing balances by daily limit, so this mainly happens when one mailbox fails or its limit was changed mid-campaign.
A shared mailbox isn't in the list: it failed its last test or was deleted. Fix it on the Mailboxes page.

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Improving Deliverability

Practical habits that keep your campaigns out of spam: warm-up, list hygiene, content and cadence.

Before you send: spam check, test email and the final check

The tools that catch problems before your email leaves: the spam check, a test sent to yourself, the pre-send check, and the blocklist check.

Sending hours, the hourly limit and the gap between emails

Send only in working hours, cap how many go out per hour, and add a random pause between emails so a campaign looks like a person, not a machine.