Why deliverability is harder than it used to be
Google and Microsoft changed the rules in February 2024. Bulk senders now need verified SPF, DKIM, and a published DMARC policy — not aspirational, actually published. One-click unsubscribe is mandatory. Spam complaints above 0.3% cause domain-wide throttling. Most Israeli SMBs running cold outbound don't know they're in violation until reply rates collapse.
Deliverability is also a moving target because it's a reputation system, not a ruleset. Two domains with identical DNS records can have wildly different inbox rates depending on their sending history, the engagement of their recipients, and the content of the message itself. A checker that only audits DNS misses 60% of the actual problem.
What this checker will audit
- SPF record syntax + alignment. Common failure: too many DNS lookups, exceeded include limits, soft-fail when you wanted hard-fail.
- DKIM signature presence and key length. We flag 1024-bit keys (deprecated) and missing selectors.
- DMARC policy. Reports whether you're at p=none (monitoring), p=quarantine, or p=reject — and what percentage your aggregate reports show as authenticated.
- Major blacklists: Spamhaus, Barracuda, SORBS, SpamCop, plus a few Israeli ISP-specific lists.
- Reverse DNS / PTR alignment with your sending IP.
- List-Unsubscribe header presence (RFC 8058, required by Gmail since 2024).
- Content red flags: spam-trigger words, link/text ratio, image-only emails, attachment risks.
- Domain age + reputation via passive lookup.
What good looks like
A green-light deliverability profile in 2026: dedicated sending domain (not your main domain), DMARC at p=quarantine or p=reject with 100% authentication, SPF with under 10 DNS lookups, DKIM at 2048-bit, custom return-path, and a sending reputation built over a 6–8 week warm-up. Most senders are missing at least three of these.
How this relates to Link AI Mailer
Mailer is our cold-email engine — it handles personalisation, sequencing, and reply detection, and runs warm-up pools that ladder up reputation automatically. The deliverability checker is the diagnostic layer that tells you whether your existing setup is the bottleneck before you change anything else.