What are the key ranking factors for Gmail inbox placement?
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If you've ever wondered why one campaign lands in the inbox and another disappears into spam, you're not imagining things. Gmail uses a layered scoring system, and a few factors carry far more weight than others.
Domain reputation comes first. Gmail builds a reputation score for your sending domain over time, based on how recipients across its entire user base respond to your emails. It's not just about your last campaign. It's about the full history of every email you've sent from that domain.
User engagement signals are a close second. Gmail watches what people do with your emails. Opens, clicks, replies, and forwards all help your standing. Deleting without reading, ignoring, and marking as spam all hurt it. This is why sending to people who actually want your emails matters so much. If you want to dig deeper into how Gmail weighs these actions, the engagement signals question covers that in detail.
Authentication is non-negotiable. Valid SPF, DKIM, and DMARC are now required for bulk senders. Without them, Gmail treats your emails with heavy suspicion. There's no workaround here.
List quality feeds into everything. High bounce rates and spam complaint rates are signals Gmail factors into your domain reputation. Gmail has enforced strict thresholds on both since 2024. A single bad send to a stale or purchased list can set your reputation back significantly. (This is the kind of damage that's slow to repair, so it's worth not causing it in the first place.)
Content quality matters too, but it's not the biggest lever. Gmail's filters do analyze for spam patterns, misleading subject lines, and phishing indicators. But if your domain reputation and engagement are strong, your content has more room to breathe. If they're weak, even clean content won't save you.
The short version: reputation and engagement are the hard ones. Authentication is table stakes and fully in your control. Content is worth getting right but won't compensate for the others.
Now you can check whether your authentication is set up correctly with our free SPF checker and DKIM lookup. If you're already seeing placement problems, our SOS hotline is free to use.
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