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exclusions: block Google consumer mailboxes (gmail) from cold/warmup sends

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Warmup audit (2026-06-08) found the main sending pool was eating a 37% bounce
rate, and 556 of those were Google 550-5.7.1 'likely unsolicited mail' spam
blocks -- of which gmail.com alone was 427 (77%). Google's cold-IP filter is the
strictest of the big providers and consumer gmail has the highest complaint
sensitivity, so mailing it from a warming IP is pure reputation damage.

Added GOOGLE_CONSUMER_DOMAINS (gmail.com, googlemail.com) to BLOCKED_EMAIL_DOMAINS,
which the daily trucking builder already enforces in its recipient SQL
(lower(domain) <> ALL(blocked)). Takes effect on the next nightly build.

Custom domains silently on Google Workspace are a smaller (~5%) MX-only signal,
already handled in the healthcare builder via the mx_provider flag; can be ported
to the main pool later if the residual warrants it.
This commit is contained in:
justin 2026-06-08 13:50:27 -05:00
parent 2156a5e05f
commit b973c6c132
1 changed files with 22 additions and 5 deletions
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27
scripts/_email_exclusions.py
View file

@ -1,10 +1,17 @@
"""Shared recipient-domain exclusions for outbound cold-email campaigns.
We self-host our MTA (transactional relays like SES forbid cold email), so we
must protect our sending-IP reputation manually. The single biggest lever is
NOT mailing the Yahoo/Verizon-Media family: those providers aggressively defer
cold senders with "unexpected volume / user complaints" 421 responses, which
poisons the IP for every other provider too.
must protect our sending-IP reputation manually. The two biggest levers:
1. NOT mailing the Yahoo/Verizon-Media family: those providers aggressively
defer cold senders with "unexpected volume / user complaints" 421
responses, which poisons the IP for every other provider too.
2. NOT mailing Google CONSUMER mailboxes (gmail.com etc.) from a cold/warming
IP: Google hard-rejects them with 550-5.7.1 "this message is likely
unsolicited mail", and those rejections are reputation-damaging. (On
2026-06-08 a warmup audit found gmail.com alone was 77% of our 550-5.7.1
blocks -- 427 of 556.) Custom domains hosted on Google Workspace are a
smaller, MX-only signal handled separately in the per-vertical builders.
Keep this list authoritative and import it everywhere we build audiences.
"""
@ -29,9 +36,19 @@ YAHOO_FAMILY_DOMAINS: frozenset[str] = frozenset({
"frontier.com", "frontiernet.net",
})
# Google consumer mailboxes. Google's cold-IP spam filter (550-5.7.1) is the
# strictest of the big providers; consumer gmail accounts have the highest
# complaint sensitivity. We hold these out of cold/warmup sends. (This is the
# domain-string layer; custom domains silently on Google Workspace need an MX
# lookup and are handled in the per-vertical builders, e.g. the healthcare
# mx_provider flag.)
GOOGLE_CONSUMER_DOMAINS: frozenset[str] = frozenset({
"gmail.com", "googlemail.com",
})
# The full set of consumer domains we refuse to cold-mail. Extend here as we
# discover other reputation-sensitive providers.
BLOCKED_EMAIL_DOMAINS: frozenset[str] = YAHOO_FAMILY_DOMAINS
BLOCKED_EMAIL_DOMAINS: frozenset[str] = YAHOO_FAMILY_DOMAINS | GOOGLE_CONSUMER_DOMAINS
def domain_of(email: str) -> str: