What is a warm-up period, and do I need one?

What a warm-up is

Providers judge a sender on history. A new account, a new domain or a new sending platform has none, so a sudden run of thousands of emails looks like the behaviour they exist to filter.

A warm-up is the answer to that. Start with a small volume, keep it regular, and raise it over days rather than in one jump. systeme.io describes abrupt swings in volume as behaviour that gets read as abnormal.

The one systeme.io runs for you

On a recent account systeme.io does this by itself, and the documentation describes no way to turn it off. It is also the first of the reasons systeme.io gives for an email sitting in a pending state instead of going out.

1. The first email goes to 100 contacts.
2. Sending is then interrupted while the early statistics are analysed. That check takes anywhere from a few minutes to six hours, depending on how much there is to process.
3. If the results are satisfactory, the next 100 go out, and the check repeats after every batch of 100 until 500 emails have been sent.
4. If the results are not, the account is moved to the quarantine pool.

Sending the email again while it is pending achieves nothing. The pause is deliberate.

What happens at 500

Two conditions have to be met before an account is classified normally: 500 emails sent, and an account more than 16 days old. After that it is placed in the low, moderate or high risk pool on its own statistics.

Which pool an account is in shows under Email, then Statistics, in the top left corner of the screen. There are five of them.

• New user. Where every new account starts, while it builds a sending history.
• Low risk. Senders with excellent statistics and consistently high deliverability.
• Moderate risk. Average but acceptable performance.
• High risk. Poor statistics that need improving as soon as possible.
• Quarantine. A temporary pool that isolates risky senders from everybody else.

Moving out of a pool later takes at least 14 days in it, plus a further volume of email before the statistics count: 500 from the new user pool, 1,000 from quarantine, and 5,000 from each of the other three.

The older advanced guide adds a floor the newer explanation leaves out: moving into the high or moderate risk bands on spam rate or bounce rate needs a minimum of 6 spam reports, and a minimum of 30 bounced emails, before that percentage counts. A small send where 2 of 20 emails bounce works out at 10%, which reads as high risk on the percentage alone, but with only 2 bounces recorded it sits under the 30-email floor and does not count yet.

It also names the identical five pools differently: Gray, Green, Yellow, Red and Quarantine, instead of New user, Low risk, Moderate risk, High risk and Quarantine.

When you have to warm up by hand

Bringing a list that already exists is the case the automatic process does not cover.

systeme.io's guidance for a large list is to send to your most engaged contacts first and raise the volume gradually over 7 to 14 days. Its re-engagement guidance puts a number on the first step: begin with 10% to 20% of the list, watch the open, click and bounce rates at each stage, then widen.

There is a figure worth knowing while you ramp. Gmail treats a send as massive once a sender passes 5,000 emails a day.

The other reasons sending stops

New account checks are one of the pauses systeme.io documents. The others catch established accounts too.

• After importing a list. Sending can be paused while the origin of the list, the state of the addresses in it and the sending domain are checked.
• Suspicious wording. An email containing words or expressions that read as spam is held until a person reviews it, then released or blocked with a reason given.
• A large send. A big newsletter can trigger an automatic verification lasting a few minutes, after which sending resumes with nothing more to do.

What a warm-up does not fix

Volume is only one of the signals. Authenticating the domain, confirming the sender address, and pointing that domain at a working homepage rather than a parking page are all conditions systeme.io lists for the first few days, alongside the ramp.

The list matters more than the schedule. Sending gradually to people who do not want to hear from you still produces low open rates, bounces from addresses that have gone stale, and complaints from people who no longer remember signing up. Those are the numbers the pool is decided on.