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Gmail's AI Inbox Is Quietly Redefining Email Deliverability

Your email landed in the inbox. Gmail's AI just decided your subscriber probably does not want to read it right now.

Filip Ivanković··3 min read
3 min read

Gmail's AI-powered inbox features are reorganising how emails surface to users, and the impact on marketing email performance is becoming measurable. Reports indicate that up to 40% of emails are being deprioritised by Gmail's AI sorting, and average click-through rates have dropped from 4.35% to 3.93% across tracked senders.

The shift is not about spam filtering. These are legitimate, opted-in emails from senders with clean reputations. Gmail's AI is making judgment calls about which emails a user is likely to care about and burying the rest. The sorting happens at the inbox level, not the deliverability level. Your email is delivered. It is just not seen.

Google has been steadily expanding AI features across Gmail, including smart categorisation, summary cards and priority sorting. Each feature adds another layer of algorithmic judgment between your send button and your subscriber's eyeballs. The cumulative effect is that inbox placement, which email marketers spent years optimising for, is no longer enough.

Why it matters

Email has been the most reliable owned channel for two decades. Open rates, click rates and conversion rates from email consistently outperform social, paid and organic channels for most businesses. If Gmail's AI meaningfully reduces email visibility, it affects the economics of entire marketing programs.

The 40% deprioritisation figure is significant because Gmail holds roughly 30% of the global email client market. In Australia, Gmail's share is even higher among younger demographics and small business users. A channel that was once predictable is becoming algorithmic.

4.35% to 3.93%

Average email click-through rate decline as Gmail AI sorting deprioritises marketing emails

The pattern mirrors what happened with organic social reach a decade ago. Platforms introduced algorithmic feeds, organic reach collapsed, and marketers had to pay to reach audiences they had already built. Email is now following the same trajectory, just more slowly.

What to do about it

Prioritise engagement signals. Gmail's AI uses recipient behaviour to decide what to surface. Emails that get opened, clicked and replied to are more likely to stay visible. Focus your list on active subscribers and prune inactive ones aggressively.

Reduce send frequency if your engagement rates are declining. Sending more emails to a list that is not engaging trains Gmail's AI to deprioritise your domain. Better to send three emails a week that get opened than five that get buried.

Test send times and subject line patterns against Gmail-specific open rates. If your ESP can segment by email client, compare Gmail performance against other clients. The gap will tell you how much Gmail's AI is affecting your results.

Diversify your owned channel mix. If email becomes less reliable, you need other direct lines to your audience. SMS, push notifications, community platforms and first-party app experiences reduce your dependence on any single channel.

Watch your Gmail-specific deliverability metrics. Google Postmaster Tools shows domain reputation and spam rate. If your reputation is strong but your engagement is falling, the AI inbox is likely the cause.

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Filip Ivanković
Filip IvankovićFounder, New Rebellion

10+ years leading performance marketing across agencies and in-house teams in Australia. Writes about the gap between marketing activity and commercial outcomes, and what it takes to close it.

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