Gmail's 0.3% spam rateHow Gmail decides your newsletter is spam, and what to check every Monday.

It is not a bounce rate and it is not SES's complaint rate. Gmail's spam rate is user-reported spam: recipients who click Report spam divided by mail Google counts as delivered to personal Gmail accounts, recalculated daily. Google's FAQ says senders should keep that rate below 0.1% and prevent it from reaching 0.3% or higher (Email sender guidelines FAQ, fetched 1 September 2026).

The rule applies once you are a bulk sender: close to 5,000 messages in 24 hours to personal Gmail accounts from the same primary domain. Google counts subdomains toward that primary domain. Hit the threshold once and bulk sender status is permanent.

You do not get a friendly warning email. Google's enforcement table lists spam rate greater than 0.3% as delivery support or mitigations unavailable (same FAQ, fetched 1 September 2026). That means if mail is throttled, rejected or foldered and you ask Google for help, they will not escalate while your user-reported spam rate is above the line, even if SPF and DKIM are perfect.

Other failures can stack on top. Missing DMARC at p=none, broken one-click unsubscribe on marketing mail, or unsubscribe requests not honoured within 48 hours put you in the same mitigation-ineligible bucket. Authentication gaps can also produce temporary SMTP error codes (4.7.x) or permanent blocks (5.7.x) before your spam rate moves.

Mitigation comes back only when Postmaster Tools shows a spam rate below 0.3% for seven consecutive days. There is no published shortcut. The fix is list hygiene: stop mailing complainers, honour unsubscribes within 48 hours, and do not re-add addresses that reported spam.

Yahoo's Sender Hub Best Practices page, fetched 1 September 2026, mirrors the authentication and complaint story with its own wording. Enforcement began in February 2024 and rolled out through the first half of the year.

Yahoo does not publish a 5,000-per-day bulk threshold on the Best Practices page. Its FAQs define bulk as significant volume without a fixed number. For Monday monitoring, treat Yahoo's 0.3% line as real even when your Gmail volume is lower.

Each provider measures a different numerator. Mixing them is how teams argue about a number that is already red in the place that matters.

If you send through Amazon SES, open the SES reputation dashboard in the AWS console at least as often as Postmaster Tools. SendBunny surfaces the same bounce and complaint percentages in Settings when AWS has enough volume to rate the account. Neither surface shows Gmail's user-reported spam rate. That gap is why Postmaster Tools stays on the Monday list.

Ten minutes is enough if you already know where each dashboard lives. Do this before you schedule a campaign or raise sending volume.

1. Open Google Postmaster Tools. Record yesterday's user-reported spam rate for each sending domain. If any domain is at or above 0.1%, pause new acquisition mail and audit the last campaign's complaint sources before you send again.
2. If any domain is at or above 0.3%, assume Gmail mitigation is unavailable. Do not request Google delivery support until Postmaster Tools shows seven consecutive days below 0.3%.
3. Open the AWS SES reputation dashboard or SendBunny Settings. Record bounce rate and complaint rate. Compare to AWS guidance: bounce under 5% and complaint under 0.1% for healthy territory.
4. Check Postmaster Tools compliance status (or your DNS records) for SPF, DKIM and DMARC on every domain you mailed from in the last week.
5. Send a test marketing message from each active list. Confirm List-Unsubscribe headers are present, the one-click POST URL works, and the address lands on your suppression list within 48 hours.
6. If you mail Yahoo addresses, confirm Complaint Feedback Loop enrollment in Sender Hub for each DKIM signing domain and scan ARF volume for the week.
7. Open your suppression list. Verify hard bounces and complaints from the last seven days are present and that no recent complainer is scheduled in an upcoming campaign.
8. Write the four numbers in one line in your runbook: Gmail spam rate, SES bounce, SES complaint, and whether auth passed. Trends matter more than any single day.

If you skip this when volume is low, the first bad list import will teach you the rule anyway. On a cold domain, a few report-spam clicks on a few hundred messages can cross 0.3% before SES complaint rate moves.

• You bought or scraped a list. No dashboard fixes that. Stop sending and clean.
• You send mostly to Google Workspace inboxes. These Gmail bulk rules apply to personal Gmail accounts, not Workspace recipients.
• You need Gmail's spam rate inside your product dashboard today. Postmaster Tools is still a separate Google login. Plan time for that tab.
• You run a dedicated IP with no history. Low volume means noisy rates. Watch longer windows, not one Monday snapshot.

SendBunny is the product layer on SES: campaigns, lists, templates, a transactional API, a shared inbox, and an MCP server for AI agents, installed into your own AWS account. It sends through your own Amazon SES at Amazon's price. $199 one time; one-click updates are an optional $99 a year. Settings shows SES account mode, sending status, bounce rate and complaint rate when AWS has representative volume, and guides the production-access request; AWS decides. Hard bounces and complaints go on an account-wide suppression list that every send path enforces. Campaigns include one-click unsubscribe. It does not replace Postmaster Tools: Gmail's user-reported spam rate still lives in Google's dashboard. It is not for you if you will not run an AWS account.