Improve email deliverability: the five levers, with the actual numbers.
Deliverability has hard thresholds now: authentication mandatory, complaints under 0.3%, bounces under 2%. Everything else is earning engagement.
Authenticate: SPF, DKIM, DMARC
Mandatory for bulk senders since 2024. Unauthenticated volume mail is filtered on arrival.
- The 60-second test: email your own Gmail, open Show original, read the three verdicts.
- SPF: exactly one record; over 10 DNS lookups breaks it silently.
- DKIM: one key per sending service; one missing key flags everything it sends.
- DMARC: at least p=none, then quarantine once reports run clean.
- Audit first: MXToolbox for blacklists, Talos for IP reputation.
Warm up on a dedicated domain
Never send cold from your primary domain. Ramp the outbound one like this:
- Week one: 5-10 emails per inbox per day, to contacts likely to engage.
- Then: +10-20% per week over 3-6 weeks. Never spike.
- Warming engine: 20-40 automated warmup emails/day, kept on during campaigns.
- Ceiling: low hundreds per inbox per day, warmed. Scale with rotated inboxes.
- Domain hygiene: neutral TLD (.com, .io, .us) + custom branded tracking links.
Keep hard bounces under 2%
Bounces tell providers you mail strangers. B2B data decays 2-3% every month.
- Verify at send time: not purchase time; Salesgear re-verifies as each sequence fires.
- Bounce auto-pause: a bad list should stop itself before it burns the domain.
- Prune non-engagers: after a finished sequence; ignores train the filter against you.
Four structural rules, all free
Content matters less than senders fear, but these four decide filter score:
- One link, max: on your own tracking domain. Shorteners are a near-automatic penalty.
- HTML under 100 KB: Gmail clips bigger mail, and clipped mail gets scrutiny.
- No trigger phrasing: act now, limited time, guarantee, all-caps subjects.
- No identical bodies: hundreds of matching sends are a bulk fingerprint; vary per recipient.
Monitor like the providers score you
Engagement is the meta-signal: opens and replies lift you, silent deletes sink you.
- Google Postmaster Tools: your reputation tier and complaint rate, as Gmail sees them.
- Read opens correctly: verified list + opens under ~40% = placement problem, not copy.
- Enforced, not homework: Salesgear runs warm-up, rotation, send-time verification, and bounce auto-pause on every inbox.
Email deliverability, answered
How do I improve email deliverability?
Work five levers in order: authenticate (SPF, DKIM, DMARC, mandatory for bulk senders since Google and Yahoo's 2024 rules), warm new domains 3-6 weeks starting at 5-10 sends a day, keep hard bounces under 2% by verifying at send time, cap volume per inbox in the low hundreds a day and ramp no faster than 10-20% a week, and keep complaint rates under 0.1% by sending relevant mail with one-click unsubscribe.
How long does it take to warm up a new sending domain?
Plan on 3 to 6 weeks. Week one: 5-10 emails per day to engaged contacts. Then increase roughly 10-20% per week, with an automated warming engine running 20-40 warmup emails a day alongside. A sudden jump from 20 to 2,000 sends reads as a compromised account and burns the ramp.
What bounce rate is safe for deliverability?
Keep hard bounces under 2%. Above roughly 3%, mailbox providers treat you as someone mailing addresses you do not know, which is the defining behavior of a spammer. B2B lists decay 2-3% per month, so verify at send time, not at purchase time.
What complaint rate gets you blocked?
Google enforces a 0.3% spam-complaint threshold for bulk senders, and sustained rates above 0.1% already hurt placement. Complaints are a targeting symptom: tighten your ICP, cap sequences at 5-8 touches, and make unsubscribing one click so people opt out instead of reporting.
Should I send cold email from my main domain?
No. Use a dedicated outbound domain (a neutral TLD like .com, .io, or .us, avoid .fun or .deal class extensions) so your primary domain's reputation is never at risk. Set up custom, domain-branded tracking links on it; shared tracking domains inherit other senders' reputations.
How do I monitor my deliverability?
Google Postmaster Tools (free, 10 minutes to set up) shows your domain reputation tier and complaint rate exactly as Gmail scores them. Pair it with your own sequence metrics: on a verified list, opens under ~40% signal a placement problem, not a subject-line problem.
Stop guessing at deliverability
Warm-up, send-time verification, rotation, and bounce auto-pause, enforced on every inbox.
Explore the deliverability optimizer