Warming up a new sending domain or list

Imagine you have just moved your membership's email to a new service, or started sending from a new domain, or decided to email a list you have not contacted in a long time. The natural instinct is to send your first message to everyone at once. That instinct can cost you dearly. To the companies that run your members' inboxes, a sudden large send from a sender they have never seen before looks exactly like a spammer testing a fresh address.

The result can be emails that arrive late, land in spam or are refused outright, and a reputation problem that takes weeks to repair. Warming up is the practice of building your sending volume gradually, starting with the people most likely to welcome your emails, so mailbox providers see a new sender whose mail people want.

When you need to warm up

Mailbox providers judge senders partly on history. A warm-up is worth planning whenever you lose that history or ask it to stretch much further than usual:

• A new sending domain, including a new subdomain used just for marketing email.
• A new email service, especially if it gives you a dedicated sending address (an IP address used only by you) rather than a shared one.
• A dormant list you have not emailed in many months.
• A large import, such as adding past event attendees or merging a second list.
• A big jump in volume, such as moving from a monthly email to several a week.

If you simply switch from one shared service to another and keep your domain, the need is smaller, but a gentle start is still sensible. Your email service may publish its own warm-up guidance; follow it where it differs from the general approach here.

Prepare before you send a single email

1. Authenticate your domain. Set up SPF, DKIM and DMARC for the new service, so receiving servers can confirm the email is really yours. Your service will give you the records to add.
2. Secure the domain itself. Make sure the account where your domain and its records are managed is protected; securing your domain name and DNS walks through it.
3. Clean the list. Remove addresses that have bounced before, obvious typos and anyone who never agreed to hear from you.
4. Keep your sender name consistent with what members already recognize.
5. Decide what to send. Warm-up emails should be your most welcome content, not a hard sell.

Rank your list by engagement

The heart of a warm-up is sending to your most engaged people first. Their opens, clicks and replies tell mailbox providers your mail is wanted. Split your list into tiers:

• Tier 1: people who clicked, replied or logged in recently. Paying members who use the site are usually here.
• Tier 2: people active within the last several months.
• Tier 3: people who have not engaged for a long time but did once.
• Tier 4: people who have never engaged, or whose last contact was years ago.

Tier 4 may never be worth sending to at all. At most, it should receive a single re-permission email asking whether they still want to hear from you, once your reputation is established.

A sample warm-up schedule

Here is an illustration for a hypothetical ceramics studio membership run by Anika, who is moving roughly 4,000 subscribers to a new service and a new sending subdomain. The numbers are examples, not rules:

1. First few sends: around 200 people from Tier 1, spread over a couple of days.
2. Next few sends: the rest of Tier 1, around 800 people.
3. Following week: Tier 1 plus the most recent half of Tier 2.
4. The week after: all of Tiers 1 and 2.
5. Then: Tier 3 added in slices, watching results after each one.

Roughly speaking, each step about doubles the volume of the last, and Anika only moves to the next step if the last one looked healthy. Over three or four weeks she reaches her full engaged list without ever sending a sudden spike.

Watch the signals and adjust

After each send, check a few things before increasing volume:

• Bounces: a spike suggests old or mistyped addresses slipped through.
• Spam complaints: any noticeable number is a reason to pause.
• Delays or deferrals: some services report when receiving servers are slowing your mail down.
• Engagement by mailbox provider: if clicks from one provider fall away while others stay steady, your mail may be landing in spam there.

If something looks wrong, do not push on. Drop back to your most engaged tier for a few sends, fix the cause and then resume more slowly.

What to send during a warm-up

Send the emails people are most likely to open and click: a genuinely useful lesson, a popular recording, the regular update members expect. For dormant or imported contacts, explain why they are hearing from you:

Subject: Still want the monthly glaze notes?

Hi Jonah,

You signed up for glaze tips at one of our open studio days a while ago. We've moved our emails to a new home, and I want to be sure you still want them.

This month's notes cover why celadon glazes crawl and how to stop it: [Read this month's glaze notes]

If you'd rather not hear from us, the unsubscribe link below takes one click.

Anika

A clear, honest reminder like this earns clicks from the people who care and a quiet unsubscribe, instead of a spam complaint, from the people who do not.

Your warm-up checklist

1. Confirm authentication is set up and passing on the new domain or service.
2. Clean the list and remove anyone who never agreed to hear from you.
3. Split the list into engagement tiers.
4. Write a schedule that starts with Tier 1 and grows step by step.
5. Choose your most welcome content for the first sends.
6. Check bounces, complaints and engagement after every step.
7. Pause and drop back if anything spikes.