If you’re using AI to scale your outbound you're likely asking the same question we hear all the time: "How many emails can I safely send per SDR without damaging deliverability?"

It’s a critical question. AI helps teams move faster and reach more prospects, but over-automation can backfire quickly. Spam filters are getting smarter, major email providers (like Google and Yahoo) are cracking down on bulk sends, and sending too many emails that recipients don’t engage with can tank your sender reputation.

Over the past year, we've tested and tracked what works (and what doesn’t) when it comes to high-volume, AI-generated outbound. Here's what we’ve learned  and how you can stay on the right side of deliverability while still scaling your outreach.

The Short Answer: Cap AI-Sent Emails at 200 Per SDR Mailbox Per Day

This recommendation comes from real-world testing and platform guidance (like Outreach), and it’s working. Sending more than 200 emails per mailbox per day starts to trigger red flags for email providers and can lead to throttling or spam filtering — even if your content is solid.

Capping at 200/day keeps your email behavior “human-like” and your domain reputation healthy.

While we recommend capping overall sends at 200/day, we recommend enrolling 50 new prospects per day to the AI sequence.

Why Email Deliverability Is Getting Harder

Over the last 12 months, even the best sales and marketing teams have seen their reply rates decline. That’s not just about bad messaging,  it’s about changes in how email providers measure engagement and flag risk.

Some key trends:

• Inbox providers now weigh engagement heavily. Opens, replies, and even deletions affect your sender reputation.
  
  
• Repetitive AI-generated emails are easy to detect. High-volume, low-variation content is a spam trigger.
  
  
• Large volume sends to cold or non-ICP contacts hurt more than help. Low engagement rates drag down future inbox placement.
  
  

If you're seeing fewer replies and more bounces, it's likely not your tools. It's your sending behavior.

6 Deliverability-Safe Practices for AI Email Outreach

1. Send Fewer, Smarter Emails

More volume doesn’t mean more replies. Focus AI outreach on high-fit accounts and prioritize prospects who’ve shown some type of signal. Avoid spraying entire cold lists — especially non-ICP audiences.

2. Stay Under 200 Emails per Mailbox per Day

This volume mimics human behavior and prevents deliverability issues tied to volume spikes. Most platforms recommend this number for consistent, safe outreach.

3. Avoid Repetitive Subject Lines

Too many AI emails use the same subject line and message structure. Clone your sequences and A/B test multiple variants or use a solution like Gem-E to ensure there are many subject variations to avoid pattern detection by inbox providers.

4. Limit Sequence Length for Low-Priority Audiences

If you’re emailing someone who hasn’t engaged and isn’t in your core ICP, keep it short. Three to four emails max. Long sequences to disengaged prospects increase negative sentiment signals (deletes, unsubscribes, ignores, or spam reports).

5. Clean and Validate Your Lists

Emails sourced through verified data partners (versus scraped or third-party lists) perform better. Make sure your emails are validated and your data sources are reliable.

6. Monitor Sender Reputation Monthly

Use tools like Mailreach and Google Postmaster to track how ISPs view your domain. Even a small increase in spam complaints can drag down inbox placement across the board.

7. Add the ability for prospects to unsubscribe

While it might seem like unsubscribes are a bad thing, reframe to think of them as providing a safe way out for recipients vs. forcing them to mark your message as spam.

Bottom Line: Quality and Consistency Beat Volume

AI gives teams the ability to scale faster than ever. But scaling outbound shouldn’t mean risking your sender reputation. The teams winning with AI outbound today are sending smarter, not just more.

By capping sends, increasing personalization, and segmenting by audience fit, you’ll see better engagement and preserve the integrity of your domain.

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