Opens fell and you suspect Gmail moved you out of Primary? Here's what actually decides the tab, what you can honestly change — and a 30-second test that shows where your next issue lands.
Nobody outside Google knows the exact formula, and anyone claiming a guaranteed 'Primary hack' is selling one. But the signals are well established — and you can check how your own newsletter scores on every one of them, on the exact issue you're about to send.
SPF, DKIM and DMARC don't decide the tab by themselves — but failing them caps everything. Mail that can't prove its origin gets treated as bulk at best and spam at worst, whatever the content. It's the first check because it's binary: pass, or start every send at a disadvantage.
Gmail files per recipient: someone who opens you weekly sees you in Primary while a cold subscriber gets you filed under Promotions — same issue, same send. That's why growth spikes and cold segments shift the average tab. Steady engagement from people who chose you is the one signal that compounds in your favor.
Multiple CTAs, big image blocks, discount phrasing, a template that looks like a storefront — each is a classic Promotions marker. A lean, personal issue with one clear link reads like correspondence. You don't have to strip your design; know which elements cost you the tab, and decide deliberately.
A steady weekly letter builds a recognizable pattern; irregular bursts look like campaigns. Consistency doesn't just help deliverability scores — it trains your readers to expect and open you, which is the engagement signal that actually moves the tab.
Complaint rates, dead addresses, past spam placements — they compound into a per-domain score every new issue inherits. A clean history won't guarantee Primary, but a damaged one guarantees Promotions or worse. Prune the list, keep complaints near zero, and check each issue before it ships.
Two honest truths most guides skip: real readers DO check Promotions, and nobody can guarantee Primary — Gmail decides per recipient. What you can control is whether your authentication passes, how promotional the issue reads, and whether you know your placement BEFORE the send instead of diagnosing it from open rates after.
You can A/B subject lines for a month and still be guessing about the tab. Or forward your next issue and see it: we open your real email in real Gmail accounts (plus Outlook and Yahoo) and show exactly where it files — with the changes most likely to move it, in plain English. About 30 seconds, free, no signup.
Test your next issueIf you've ever searched "email tester," half the results check whether the address is valid. We do the other thing — whether the email itself will reach the inbox once you press send.
You upload a CSV of subscribers. The tool tells you which addresses bounce. Great for cleaning a stale list before a re-engagement send.
You forward one email — newsletter, launch, client note — to a one-time mailbox. We open it in real Gmail, Outlook, and Yahoo and tell you which tab it landed in, plus what to rewrite before you send it to your list.
Paste the mailbox above into the test-send field in Beehiiv, Kit, Substack, Mailchimp — or your own inbox. Hit go. We never see your subscriber list.
In real Gmail, real Outlook, real Yahoo. We watch where your email lands — Primary, Promotions, or Spam — using the same filters that decide whether your campaign worked.
Plain English. Three things to change, in priority order. Unlock the bundle and we generate a subject, body, and CTA rewrite in your voice — paste them back into your campaign before lunch.
Forward any email and get the score — free and unlimited. Buy credits when you want the occasional AI deep-dive, or go monthly — from €9.99 — if you send regularly. Cancel from the same screen you upgrade on.
Takes less time than picking a hero photo. No card, no signup, no anything.
