Warming up a new domain

When you send your first campaign from a new domain in Wiz, it automatically goes through a warmup first, and it helps to understand why. Inbox providers (Gmail, Outlook, Yahoo, and the rest) have no history with a brand-new domain yet, so they don't know whether to trust your emails. Sending a big campaign to everyone right away, before you've earned that trust, is the fastest way to land in spam. Warming up solves this: Wiz eases your first campaign out gradually so providers can get to know you, protecting your reputation from day one.

This guide explains how the warmup works and how to get the best possible result from it.

Why warming matters

Inbox providers decide inbox-vs-spam largely on your sender reputation, and a new domain starts with none. During these first sends, providers watch closely how people react: do they open, click, and reply, or ignore and delete? Strong early engagement tells them your mail is wanted and builds your reputation; a large, low-engagement blast does the opposite and can get you filtered for a long time. Warming up is about making those first impressions count.

How Wiz warms your domain

Instead of sending your first campaign to everyone at once, Wiz releases it in stages:

• It starts with your most engaged subscribers (the people most likely to open and click) and expands to the rest in gradually increasing batches.
• Sends are grouped by inbox provider, so each one is introduced to your sending at a healthy pace.
• The whole warmup usually takes 2 to 3 days to finish, depending on your list size, and you'll see its progress as it sends.

Leading with your most engaged people is deliberate: their strong response sets a positive tone that helps the later batches land in the inbox too.

How to get the best warmup

This first send matters more than a normal campaign, so set it up to earn opens and clicks:

• Send it to all your subscribers. A single, full warmup send is what establishes your baseline sending volume, so don't break it into small pieces.
• Write a strong subject line and preview text. Opens are the biggest positive signal at this stage, so make the subject genuinely worth clicking.
• Give people a reason to engage. An appealing offer or discount in this first campaign lifts opens and clicks, which directly strengthens your reputation.
• Proof it before it goes out. Send yourself a test and check for broken images, typos, and links that don't work. You only get one first impression.

What to avoid

• Don't schedule another campaign while the warmup is running. Let it finish first, since a second send on top disrupts the gradual ramp that's building your reputation.
• Don't jump straight to a huge send afterward. Sudden spikes in volume look suspicious to providers. Grow steadily instead (see below).
• Avoid deadline-driven content in this send, for the timing reason above.

What to expect

• Your subscribers receive the email in waves over a few days, not all at the same moment. That's the warmup working as intended.
• The open rate on your warmup send is a useful early read on how healthy your list is.
• Your flows aren't affected. Automations like Welcome and Abandoned Checkout keep sending normally; warming applies to your campaign sends.

After the warmup

Once it completes, you have a starting reputation to build on. Keep it growing:

1. Start your next campaign with Wiz's recommended segment rather than the full list again.
2. Widen your audience gradually, as long as your open rates stay healthy.

See Email deliverability best practices and Choosing your audience to keep improving from here.

Common questions

How long does warming take?

Usually 2 to 3 days, depending on how many subscribers you have. Wiz shows the progress as it sends.

Can I send other campaigns during the warmup?

No, wait until it finishes. Sending on top of an active warmup disrupts the gradual ramp that's building your reputation.

Do my automated flows get warmed too?

Warming applies to your campaign sends. Your flows keep running normally the whole time.

Why did engagement look different across the send?

Because Wiz sends to your most engaged subscribers first, the early waves often show higher opens and clicks than the later ones. That's expected.

Updated on: 27/07/2026