Email sequencer
Software that sends email sequences from connected mailboxes on a schedule, inserts personal details, stops on replies and reports results per sequence.
What it means
A sequencer connects to one or more sending mailboxes and sends each contact the steps of a sequence at set intervals, with merge fields for names and company details, often spintax for variation, and automatic stops when someone replies or books a meeting, as HubSpot's sequences do. Reports show reply, bounce and unsubscribe rates per sequence.
Cold email sequencers often spread sending over many mailboxes and domains. M3AAWG's position on cold email describes that pattern (multiple sending accounts, lookalike domains, random intervals, personalisation that makes bulk mail look one-to-one) as deceptive when used to avoid spam filters.
The mailboxes a sequencer uses keep their providers' sending limits, which still apply per account.
Related terms
On this site
Sources
What this definition rests on. The wording is ours; the facts are theirs.
- HubSpot: Create and edit sequencesknowledge.hubspot.com
- HubSpot: Analyze sequence enrollment and performance dataknowledge.hubspot.com
- M3AAWG Position on Cold Email (November 2025)m3aawg.org
- Google Workspace Admin Help: Gmail sending limits in Google Workspacesupport.google.com
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