Sales sequences only work if they reach the inbox, and inbox providers judge each rep's sending behavior individually. The goal is simple: HubSpot-sent sales emails should be indistinguishable from emails a rep wrote by hand. These are the rules we set for clients to get there.
Why deliverability is a sales problem
Email deliverability is a shared reputation. It takes months to build and days to damage. Sending too much, too fast, or to the wrong people trips Gmail and Outlook spam filters, and once a domain is flagged, open rates collapse and every rep's outreach suffers.
This guidance covers sales email: one-to-one outreach and sequences. It doesn't cover bulk marketing email, which goes to opted-in contacts through separate tools and rules.
Two core principles
- Individual sender reputation: providers score each sender separately, based on how recipients interact with their emails.
- The human assistant model: use HubSpot to imitate human sending. Vary send times, personalize, add delays and segment carefully so nothing looks automated.
Sending architecture
Every rep sends from their own individual email address. Never prospect from shared addresses like sales@ or info@: they signal impersonal outreach, hurt deliverability, and make it impossible to see which rep has a problem.
Sending limits
- Warmup: a new sending address sends only 20–30 emails a day for the first 2–4 weeks, to the highest-quality contacts.
- Steady state: a maximum of 100 emails a day per rep.
These are ceilings, not targets. Fewer, well-chosen emails beat high volume every time.
Sequence guardrails
- Plain text only: no HTML templates, images or logos. Plain text reads as person-to-person and gets delivered.
- Manual enrollment only: reps review and enroll each prospect, with no automated triggers.
- 2–3 business days between touches: it gives prospects time to respond and looks like natural sending.
- 3–5 touches maximum for cold outreach.
List quality rules
- Relevant prospects only: before enrolling anyone, ask why your solution matters to this person now. If you can't answer, don't send. Enforce clear ICP criteria and have managers audit enrollments.
- No purchased or scraped lists: they bring outdated addresses, bounces, spam traps and recipients with no context. Build lists from LinkedIn research, company websites, referrals, events and people who've engaged with your content.
Monitor and pause
- Open rates: aim for 20–25% on new contacts. If a rep falls below 15% for three days, pause and investigate.
- Bounces: above 3% means the list is bad. A sudden spike means stop and check the data.
- Automatic pause triggers: bounces over 5%, opens under 10% for five days, spam complaints over 0.1%, or any blacklisting.
Allowed vs. not allowed
| Allowed | Not allowed |
|---|
| Plain-text emails that read like a personal message | Designed templates with images or logos |
| Enrolling prospects one by one after review | Automatically enrolling contacts without checking |
| 2–3 days between touches | Follow-ups the same or next day |
| Up to 100 emails a day per rep | More than 100 a day from one address |
| New senders warming up at 20–30 a day | Mass sends to large groups at once |
| Contacts from research that fit your ICP | Bought or scraped lists |
| Stopping as soon as performance drops | Sending through high bounces or complaints |
The golden rule: if you wouldn't send it this way from your own Gmail, don't send it through HubSpot.
Pre-launch sequence checklist
- Inbox health: opens above 20%, bounces under 3%, no complaints.
- Personalization goes beyond first name to company specifics or pain points.
- List quality: ICP fit, corporate emails, relevant titles.
- Manual enrollment with a clear reason for each contact.
- Timing: at least 2 days between touches and sensible send times.
- Volume: projected sends under 100 a day (30 during warmup).
When something goes wrong
- The rep pauses all sending and records what triggered it.
- The manager finds the root cause in the list, content, volume or contact fit, looking back over 30 days.
- Fix it and set exit criteria, for example bounces under 2% and opens over 25%.
- The admin re-enables sending at warmup volume, and the manager watches daily for 14 days before raising it.
Frame this as protecting shared infrastructure, not discipline.
Gmail vs. Microsoft 365
- Gmail reacts fast: emails can hit spam within a day or two, but reputation can recover in 2–3 weeks once sending improves.
- Microsoft 365 reacts slowly but hits harder: filtering may take 1–2 weeks to start, recovery can take 4–8 weeks, and problems can affect the whole company's email. SPF, DKIM and DMARC matter a lot here.
Governance
Name one email deliverability owner, usually a sales or RevOps lead, with authority over sending rules. Review open, bounce and spam metrics with sales leadership for 30 minutes a week, and document who can pause sending (the owner and managers) and who can re-enable it (the owner only).
Protect your inbox access as if your pipeline depends on it, because it does. Talk to CRM Assist about a sending policy for your team.