Deliverability

Email deliverability refers to whether your emails successfully land in the inbox (primary, promotions, or updates tabs) versus being filtered to spam or blocked entirely. It is distinct from delivery rate, which only measures whether the email reached the recipient's server — a message can be "delivered" to the server and still land in spam. True deliverability is inbox placement, and most ESPs don't measure it directly. Third-party tools like Google Postmaster Tools, Mail-Tester, and GlockApps give creators visibility into actual inbox placement rates. The factors ISPs use to determine inbox placement fall into three categories. Authentication is binary — SPF, DKIM, and DMARC must be configured correctly or the mail fails or goes straight to spam. Sender reputation is a score maintained by ISPs (particularly Gmail's reputation system and Microsoft's SmartScreen) based on your sending history: bounce rates, spam complaint rates, engagement rates, and how long you've been sending. List quality is the factor most creators underestimate — sending consistently to subscribers who never open trains ISP algorithms to deprioritize your emails. Gmail explicitly uses engagement signals (opens, clicks, move to inbox, replies) to personalize inbox placement per recipient. Spam complaint rate is the deliverability metric with the lowest tolerance. Gmail and Yahoo's 2024 bulk sender requirements set a hard threshold of 0.3% spam complaint rate before throttling begins, and 0.1% before warnings appear in Google Postmaster Tools. For a 10,000-subscriber list, that's 30 complaints per send at the warning threshold. The most common cause of elevated complaint rates is misaligned expectations: subscribers who don't remember signing up, or whose interests have drifted from the newsletter's topic. A re-engagement campaign that removes non-openers proactively lowers complaint risk more effectively than any technical fix. Creators who send from a custom domain with properly configured SPF, DKIM, and DMARC and maintain engaged lists typically achieve 95%+ inbox placement. Poor deliverability compounds silently — subscribers who never see your emails cannot open, click, buy, or convert, and the revenue loss is invisible in your dashboard unless you're specifically measuring inbox placement alongside send metrics. The fastest way to diagnose a deliverability problem is to send yourself a test from your production sending environment, check which tab it lands in (Primary, Promotions, or Spam), then check Google Postmaster Tools for your domain-level reputation score. A domain reputation of 'Low' on Postmaster Tools means Gmail is actively deprioritizing your emails for most recipients. Recovery takes 4–8 weeks of clean sending: reduced volume, suppressed inactive subscribers, and zero spam complaints. InfluencersKit surfaces domain reputation indicators directly in the analytics dashboard so deliverability problems surface before they compound. The three most impactful actions for a struggling domain reputation, in order: suppress anyone who hasn't opened in 90+ days, add DMARC p=quarantine if not already set, and reduce send frequency by 50% until reputation recovers.