Email deliverability

Overview

The best cold email in the world earns nothing from the spam folder.
Deliverability is mostly infrastructure and reputation, not words. Fix the
plumbing first; then copy (see cold-email-writing) does the rest.

Three things decide placement: authentication (are you who you say you are),
reputation (do mailbox providers trust this domain/IP), and engagement
(do recipients open, reply, and not complain).

1. Authenticate - the non-negotiable trio

Record	What it proves	Rule
SPF	which servers may send for your domain	one SPF TXT record, all senders listed
DKIM	the message wasn't altered and is signed by you	enable DKIM signing on every sending platform
DMARC	what to do when SPF/DKIM fail + where to report	publish a DMARC record; start p=none, move to quarantine/reject

As of the Google/Yahoo 2024 bulk-sender requirements, senders above ~5,000
messages/day to Gmail/Yahoo must have SPF, DKIM, and DMARC, one-click
unsubscribe, and keep spam complaints under ~0.3%. Treat these as table stakes
for any sender now, not just bulk.

2. Protect your main domain - send from a separate one

• Never run cold outbound from your primary domain (company.com). Burn it
  and your invoices, contracts, and real mail go to spam too.
• Buy lookalike sending domains (getcompany.com, company-hq.com), host the
  mailboxes there, and redirect them to your main site.
• Keep ~2-3 inboxes per domain, and spread volume across domains/inboxes.

3. Warm up, then ramp slowly

A brand-new domain/inbox has no reputation. Rules of thumb (not hard law):

• Warm up 2-4 weeks before real sends - automated warmup exchanges + a trickle
  of genuine mail.
• Ramp volume: start low (~10-20/inbox/day), increase gradually over weeks to
  a steady cap (commonly ~30-50/inbox/day for cold). Don't spike.
• Pace within the day - even spacing beats a burst at 9:00am sharp.

4. List hygiene

• Verify every address before sending; keep bounce rate under ~2-3%. High
  bounces are the fastest reputation killer.
• Remove role addresses (info@, sales@), catch-alls you can't verify, and
  anyone who hasn't engaged across a whole sequence.
• Honor unsubscribes/opt-outs instantly. Keep complaints under ~0.3%.

5. Monitor placement

• Watch Google Postmaster Tools (domain reputation, spam rate, auth results).
• Run periodic seed/inbox-placement tests across Gmail/Outlook/Yahoo.
• Track reply rate as a proxy - a sudden drop often means you're in spam, not that
  the copy got worse.

Do / Don't

• Do authenticate (SPF+DKIM+DMARC) before the first send.
• Do keep bounces <~2-3% and complaints <~0.3%.
• Don't send cold from your primary domain, ever.
• Don't ramp fast or blast a cold list on day one - reputation is earned slowly.

Common mistakes

• DMARC never advanced past p=none, or multiple conflicting SPF records.
• One inbox blasting hundreds/day → throttled or blocklisted.
• Buying an unverified list and sending immediately (bounce spike → domain dead).
• Blaming the copy when the real problem is placement; check Postmaster first.

Go live with Chronos (optional)

Chronos handles the operational side of this for you on your connected inbox:
automated warmup, per-inbox daily caps, even per-minute pacing, and send-window
timing are built into the sending engine - you don't hand-tune cron jobs.

• geo_create_campaign / geo_launch_campaign - sends ramp and pace automatically.
• geo_get_campaign_benchmarks - watch reply/bounce health per campaign.
• geo_get_connection_page - connect the sending inbox (Gmail/Outlook/SMTP/AgentMail).

You still own domain DNS (SPF/DKIM/DMARC) - set those up as above before connecting.

Connect in ~30s → `CONNECT-CHRONOS.md`. Free, no card.

See also: cold-email-writing, multichannel-sequences, outbound-metrics-and-benchmarks.