How do you write a re-engagement email sequence?

Three emails, one clear choice, then a clean list.

What is a re-engagement sequence?

A re-engagement sequence is a short series of emails sent only to subscribers who have gone quiet. Its job is to get one signal from each of them: a click, a reply, or an unsubscribe. People who give no signal at all are removed from regular sends. It is one of the standard campaign types in a B2B email programme, and the only one whose success is measured partly by how many people it removes.

This matters more in B2B than most teams expect. Business addresses change when people change jobs, security tools click links on a person's behalf, and a list built from a lead magnet two years ago is full of people who downloaded one PDF and never came back. Sending your next launch sequence to all of them costs you reputation with Gmail and Outlook for no return.

Why can't opens define "inactive" any more?

An open is recorded when a tiny invisible image in the email loads from the sender's server. Mailchimp's own documentation explains that this fails when images are blocked, cannot work in plain-text email, and gets inflated by bots and by Apple's Mail Privacy Protection. Apple says the feature prevents senders from seeing if you have opened the email they sent you. In practice, Apple Mail loads the image whether or not the person ever reads the message.

So an open-based rule fails in both directions. A subscriber on Apple Mail looks active while ignoring every issue. A subscriber on a corporate Outlook with images off looks dead while reading every one. Clicks are better, though corporate security scanners can click links too. Replies are the cleanest signal of all: a scanner never writes back. Sawa's rule is to define inactive by clicks and replies, and to treat opens as a tie-breaker at most. Our guide to newsletter metrics that matter goes deeper on which numbers you can still trust.

How long should someone be silent before they count as inactive?

There is no industry standard, and the platforms disagree. Kit fixes it at 90 days without an open or click (30 days for new subscribers) and does not let you change it. HubSpot counts emails rather than days: 11 unengaged sends for someone who never engaged, 16 for someone who once did. Mailchimp leaves the window to you and offers presets from 7 days to 3 months.

Sawa's starting rule is 90 to 180 days without a click or reply. Use the short end if you send weekly, because 90 days is already a dozen ignored issues. Use the long end if you send monthly, because 90 days is only three sends and one of them may have landed during a holiday. Walk through this list to set your own definition:

1. Pick the signal. Clicks and replies. Add opens only if your audience is mostly on clients that do not preload images, and even then, do not rely on them alone.
2. Pick the window from your cadence. Weekly senders: 90 days. Biweekly: 120 days. Monthly: 180 days. The point is a window that covers at least ten sends, so one missed email cannot flag someone.
3. Protect new subscribers. Anyone who joined in the last 30 days is still in the welcome sequence and should not be in this one.
4. Protect live relationships. Exclude open deals, active customers and anyone your sales team spoke to in the window. The CRM knows this; the email platform usually does not.
5. Write the rule down. One sentence, with the numbers in it, saved next to the segment so the next person does not guess.

How do you build the segment?

Turn the rule into a saved segment in your email platform. The shape is the same everywhere: subscribed, joined more than 30 days ago, no click in the last N days, no reply in the last N days, and not tagged as a customer or open opportunity. Some platforms cannot see replies, so you may need to tag repliers by hand or through your CRM before the segment runs.

Build it as a live segment rather than a one-off export. A live segment lets the sequence run on a schedule, monthly or quarterly, so list hygiene becomes a habit rather than a project. List hygiene is the routine of removing addresses that no longer respond; our glossary entry covers the related terms.

What are the three emails?

Three emails over about two weeks. Each one asks for a single action, and each has a different reason for the subscriber to take it. The subject lines below are illustrative. Write your own in the voice your subscribers already know.

Email 1: the check-in

Short, plain, and honest about why you are writing. Name the gap ("you have not clicked anything from us since spring") and give one reason to stay that is specific to them: the issue that got the most replies, a template they can use today, a change in what you cover. Do not apologise, and do not ask for a survey. One link.

Email 2: the best-of or what changed

A week later, show them what they missed. Either the two or three most-clicked pieces from the window (a best-of), or what has changed since they last engaged: a new format, a new cadence, a new focus (a what-changed). Pick whichever is more true. A best-of works when the content was strong and the subscriber drifted. A what-changed works when the content was the problem and you fixed it.

Email 3: the choice

The last email is binary. Two links, stay or go, and a plain sentence saying that no click means you will stop emailing them in seven days. This is the email that makes the sequence work, because it turns silence into a decision the subscriber made rather than one you made for them. Many people who click "stay" here never clicked anything else; the deadline is the reason.

What happens after the last email?

Seven days after email 3, everyone who did not click or reply leaves the active list. You have two options, and both protect your sending reputation.

Remove. Unsubscribe or delete the contact. This is the simplest, and on platforms that bill per contact it lowers the bill. Mailchimp's own advice for subscribers who do not respond to a few re-engagement attempts is to archive them.

Suppress into a low-frequency segment. Keep the contact but exclude them from regular sends. They receive at most a quarterly note, or nothing until they act. This suits B2B lists where the address is also a CRM record with deal history that sales does not want deleted. HubSpot does a version of this automatically: its "don't send to unengaged contacts" setting is on by default and skips contacts who have ignored the last 11 or 16 emails.

Whichever you choose, write it into the sequence. Email 3 promised a deadline, and keeping it is part of what makes the next re-engagement run credible.

Why does removing people protect deliverability?

Mailbox providers judge senders by how recipients behave. When a large share of your recipients ignore, delete or report your email, Gmail and Outlook route more of it to spam, for everyone on your list, not just the quiet ones. HubSpot's documentation puts it directly: continuing to send to contacts who do not open or click lowers your overall sender score.

Google now sets hard numbers. Senders of more than 5,000 messages a day to Gmail accounts must keep their spam rate in Postmaster Tools below 0.10% and avoid ever reaching 0.30%, and marketing email must support one-click unsubscribe. Inactive subscribers are the people most likely to hit "report spam" when a message surprises them, so every quiet address you keep is a small bet against that threshold. Removing them is not losing audience. It is removing risk from the audience that is still reading. This is why the sequence belongs in the convert stage of how Sawa runs campaigns: it clears the way for the sequences that produce meetings.

What should you measure?

Three numbers, all counted by click or reply, never by open.

1. Reactivations. Subscribers in the segment who clicked or replied to any of the three emails, as a share of the segment. Split it by email so you learn which reason to stay actually worked.
2. Explicit leaves. Unsubscribes and "go" clicks. A high number here is not a failure. Those people were never going to buy, and they have just stopped counting against you.
3. Removals. Everyone who gave no signal and was removed or suppressed. Track the list size before and after, and the spam rate in Postmaster Tools in the month that follows.

Expect the reactivation share to be small and the removal share to be large. That is the sequence working, not failing. A run that reactivates a modest minority and cleanly removes the rest leaves you with a smaller list whose clicks, replies and meeting requests per send go up, which is the number the business actually cares about. Run the sequence again on the same rule every quarter, and the segment should get smaller each time.

Need help with this? See how Sawa handles campaigns that convert, or book an intro call.