We get the ticket every week. "Gmail put us in Promotions. How do we get back to Primary?"
That is usually the wrong question.
Gmail deliverability is a wanted-mail problem. If people ask for the email, open it, and rarely hit spam, you do fine. If they ignore you for a year and then mark you as junk, no header trick saves you.
TL;DR: What Gmail actually cares about
- Authenticate. Bulk senders need SPF, DKIM, and DMARC. TLS on the connection too.
- Watch complaints. Aim under 0.1%. Around 0.3%, blocking gets likely.
- Mail engaged people. Opens and clicks matter. Cold lists drag you into spam.
- Use Postmaster Tools. Domain reputation beats guessing from open rates.
- Promotions is still inbox. Stop spending weeks trying to outsmart the tab sorter.
What to watch out for: buying lists, blasting years of silent contacts, and filing Google's remediation form before you clean your own house.
For the broader spam picture, start with why emails go to spam. For sender setup habits that train placement, see predicting inbox placement.
Gmail deliverability starts with authentication
Gmail used to treat SPF, DKIM, and DMARC as "you should." For bulk senders, they are required now.
SPF says which IPs can send for your domain. DKIM signs the message so Gmail can prove it was not swapped in transit. DMARC tells them what to do when those checks fail. Skip any of that and you look like every phisher with a free form tool.
TLS is required too. Unencrypted SMTP used to get a little unlocked icon. Now encryption is part of the documented bar for bulk mail. Your ESP should already speak TLS. If someone is still shipping plain SMTP in 2026, that is a platform problem, not a copy problem.
None of this fixes a permission mess. Auth gets the message accepted. Engagement decides if you stay.
If you are sorting out Yahoo and Gmail bulk rules at the same time, our MAGY compliance notes cover the shared checklist.
Complaint rates are the hard number
Gmail listens to the spam button. Closely.
Their guidance for bulk senders is blunt. Keep spam complaint rates under 0.1%. Cross about 0.3% and you should expect blocking or hard spam folder placement.
That is a tiny fraction. Send 100,000 messages and 100 complaints puts you at the line. Three hundred complaints and you are in the danger zone. One purchased list can burn months of good sending in an afternoon.
We see the same pattern in support. The campaign looked fine. Subject line was fine. Then Postmaster Tools shows a complaint spike and inbox rates fall for everything from that domain. The fix is almost never the button color. Stop mailing people who never wanted this.
Do not buy or rent lists. Do not scrape. Do not "re-engage" a CSV from 2019 because finance wants the open rate up. Gmail is good at spotting that feedback. Cleaning up afterward is slow and boring.
Engagement is the filter
Gmail's spam systems lean hard on engagement. Opens, clicks, replies, deletes without reading, spam reports. The mix tells them whether your mail is wanted.
You will meet marketers who swear engagement "doesn't matter anymore." They are wrong. What got you into the inbox in 2019 is not automatically good enough in 2026. Thresholds move and filters get pickier. Wanted mail still wins.
When inbox placement slips, the common operator fix is simple. Mail only people who opened or clicked in the last 9 to 12 months. Hold that for at least 30 days. If the mail is actually wanted, placement usually recovers.
Then decide what to do with the quiet majority. Sunset them. Send a plain "still want this?" note, then stop. Keeping dead weight on the list to protect vanity list size is how you train Gmail to distrust the whole domain.
This is list hygiene, not a secret MIME header. Almost every "Gmail hates us" ticket we dig into ends in low engagement or weak permission, not a missing technical flag. Check auth and bounce handling with your ESP. Then look at who you are mailing.
Postmaster Tools over vibes
Register your sending domains in Google Postmaster Tools. You get domain and IP reputation, spam rate trends, and authentication results when volume is high enough.
The charts can feel cryptic. Gaps appear. Scores jump without a clean story. Still use it. Open rate from your ESP is a lagging, noisy proxy. Postmaster is closer to what Gmail thinks of you.
Watch spam rate and domain reputation after big sends, list imports, and warmups. If reputation drops, shrink to recent engagers before you ramp again. Guessing from a single campaign's click rate is how people make the hole deeper.
The remediation form is not a cheat code
Google has a bulk sender remediation form. You submit a sample message, explain the case, and ask them to reconsider filtering.
Use it after you are sure the basics are solid. Authenticated. TLS. Complaint rate under control. Sending to people who opted in and still engage. If you are still mailing purchased lists or years of silence, you are wasting the form and your week.
They review submissions. They do not usually send a chatty reply. Sometimes filters move if your case is strong or points at a real bug. Even then, they warn it can take around two weeks before you see inbox changes. File it, keep sending clean mail, keep watching Postmaster. Do not sit idle waiting for a magic unlock email.
Promotions still counts as inbox
Marketing mail belongs in Promotions a lot of the time. That is the product working.
Fighting the tab sorter is an arms race you lose. Gmail wants promo content in Promotions. Landing there is not spam. The message still reached the inbox. People who care will check the tab. People who do not care were not going to buy from Primary either.
We wrote more on this in the Promotions tab reality check. Spend your energy on wanted mail and separate FROM addresses for transactional vs marketing, not on tricking classifiers for a week of Primary placement.
Spam folder is the failure mode. Promotions is a filing cabinet.
What to do this week
- Confirm SPF, DKIM, and DMARC for every domain and subdomain you send from. Confirm TLS with your provider.
- Open Postmaster Tools. Note spam rate and domain reputation for the last 30 days.
- Cut the next few campaigns to openers and clickers from the last 9 to 12 months.
- Plan a sunset for the rest. Do not keep mailing them "just in case."
- Only then, if placement is still broken and your house is clean, use the remediation form.
Predictable senders help too. Keep receipts and password resets off the same FROM address as the weekly promo. That trains Gmail, Yahoo, and Outlook on where each stream belongs. Details are in predicting inbox placement.
Takeaways
Gmail deliverability is mostly complaint rate and engagement. Authentication gets you accepted. Cold lists are the problem. Promotions is just a filing cabinet.
If you send with Bento, start with Authors split by email type, keep an eye on complaint and bounce metrics, and treat list sunsetting as part of the send plan, not a once-a-year chore. Questions? Ask in Discord.