How AI SDRs Optimize Email Infrastructure

AI-powered Sales Development Representatives (SDRs) can revolutionize your email outreach, but their effectiveness hinges on one critical factor: email deliverability. Without the right infrastructure, even the smartest AI systems will fail to land emails in inboxes. Here’s what you need to know:

• Email deliverability ensures your messages avoid spam folders and reach prospects. Poor infrastructure can drop deliverability rates from 95% to under 50% in just 3-6 months.

• Authentication protocols like SPF, DKIM, and DMARC are essential to prove your emails are legitimate and protect your domain’s reputation.

• IP reputation and email throttling help manage sending volume, prevent spam flags, and ensure consistent inbox placement.

Key Steps to Build Strong Email Infrastructure:

1. Set up SPF, DKIM, and DMARC to authenticate your domain.

1. Warm up new domains and IPs gradually to establish trust with email providers.

1. Use tools like Google Postmaster Tools to monitor metrics like bounce rates and spam complaints.

1. Maintain low complaint rates (below 0.1%) and clean email lists to protect your reputation.

Your email infrastructure isn’t just technical - it directly impacts revenue. By prioritizing deliverability, you’ll maximize the ROI of your AI SDR campaigns.

How to Properly Set Up Cold Email Infrastructure [Best Method 2026]

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Core Components of Email Infrastructure

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Building a strong email infrastructure relies on three key protocols: SPF, which identifies authorized senders; DKIM, which ensures message integrity; and DMARC, which enforces sender rules [11][12]. Without these, your AI SDR's emails may never make it to a prospect's inbox. Let’s break down these authentication protocols.

Domain Authentication: SPF, DKIM, and DMARC

SPF (Sender Policy Framework) is a DNS record that lists the IP addresses and servers allowed to send emails on your domain’s behalf [11][12]. When an email is received, the server checks the SPF record to confirm the sender is authorized. Be mindful of the 10 DNS lookup limit - if you’re using multiple systems (like CRM tools or AI SDRs), consider consolidating or using subdomains [10][13].

DKIM (DomainKeys Identified Mail) adds a cryptographic signature to email headers, ensuring the message remains unaltered during delivery [11][12]. The receiving server uses a public key from your DNS to verify the signature. To strengthen security, use 2048-bit DKIM keys [10][11].

DMARC (Domain-based Message Authentication, Reporting, and Conformance) connects SPF and DKIM by verifying that the visible "From" address aligns with authenticated domains [9][11]. It also instructs servers on how to handle failed authentications: p=none (monitor only), p=quarantine (send to spam), or p=reject (block entirely). Starting February 2024, Google and Yahoo will require bulk senders (5,000+ emails daily) to have at least p=none DMARC to avoid being throttled or blocked [10][11].

Authentication significantly impacts deliverability. Fully authenticated B2B senders are 2.7 times more likely to reach inboxes than those without authentication [10][3]. Surprisingly, only 18.2% of the top 10 million domains have a valid DMARC record, and just 7.6% enforce strict policies [10][3]. This gap is an opportunity for AI SDR users who prioritize proper authentication.

"Treat email authentication like a revenue project: if the inbox can't trust you, your prospects can't reply to you." - SalesHive [10]

Start with p=none to monitor activity, then transition to stricter policies (p=quarantine and eventually p=reject) to protect your domain. To safeguard critical communications like invoices or internal emails, run AI SDR outreach from subdomains such as hello.company.com [10][3].

IP Reputation and Its Impact on Deliverability

Authentication alone isn’t enough - your sender reputation plays a crucial role in email deliverability. IP reputation is essentially a trust score assigned to the IP address sending your emails [14][15]. Servers often block emails from low-reputation IPs before even analyzing their content [15]. For AI SDRs sending high volumes, maintaining a strong reputation is essential.

Reputation builds over time through consistent sending patterns, low complaint rates, and clean email lists [14][16]. However, with 45% of global email traffic classified as spam (over 162.7 billion spam emails sent daily in 2025), mailbox providers are highly cautious [3]. For example, Google and Yahoo require spam complaint rates below 0.3%, but staying under 0.1% is ideal for maintaining a healthy reputation [3][5].

Businesses must decide between shared and dedicated IPs:

• Shared IPs: Ideal for low-volume senders, as they benefit from the established reputation of the email service provider (ESP). However, other senders’ poor practices can harm your deliverability [14].

• Dedicated IPs: Best for high-volume senders (10,000+ emails per month). While they offer full control, they require a warm-up period to build a reputation from scratch [2][14].

When using a new IP, avoid sending at full capacity right away. Start with 10–20 emails per day to engaged contacts and gradually increase over 4–8 weeks [2]. To protect your primary domain’s reputation, use dedicated subdomains like outbound.company.com for AI SDR outreach [16][3]. Monitor tools like Google Postmaster Tools and Microsoft SNDS to track your IP’s reputation, categorized into "buckets" such as Bad, Low, Medium, or High [15][2].

The Role of Email Throttling

Throttling - controlling the volume of emails sent - completes the foundation of email infrastructure. Sending too many emails too quickly, even if they’re well-crafted, can trigger spam filters [1][6][17]. Throttling ensures compliance with provider-specific limits and prevents your domain from being flagged.

For cold outreach, a single inbox (e.g., Gmail or Outlook) should send no more than 50 emails per day, including warm-up emails [1][17]. Bulk senders (5,000+ emails daily) face stricter rules from providers like Google and Yahoo, which require proper authentication to avoid throttling or blocking [3][7]. When starting with a new inbox, begin with as few as 1–5 emails per day and gradually increase volume [6][1].

Spread email sends throughout business hours rather than batching them all at once. For example, instead of sending 200 emails at 9:00 AM, distribute them evenly over the day to avoid triggering filters [2][14]. To scale beyond 50 emails per day, add more inboxes instead of increasing volume on a single account - a technique called inbox rotation [1][17].

"If you get throttled, tap the brakes and slow it down." - Twilio SendGrid [6]

Dynamic throttling adjusts your sending volume based on real-time feedback. If you notice high bounce rates, spam complaints, or signs of throttling from providers, reduce your volume immediately [6][1]. Tools like Google Postmaster Tools can help identify issues with reputation or throttling, guiding you to maintain steady, predictable sending patterns that build trust over time.

Preparing Your Email Infrastructure for AI SDRs

Before deploying an AI SDR, it's essential to evaluate your email infrastructure. Conducting a detailed audit and gradually warming up your email accounts can significantly extend your domain's lifespan - potentially from 3 months to over 9 months - while boosting deliverability rates by more than 4% while improving sales team productivity [21]. This preparation lays a solid foundation for smooth mailbox warmup and long-term deliverability management.

Auditing Your Current Email Infrastructure

Start by ensuring that SPF, DKIM, and DMARC are properly configured. Tools like Google Postmaster Tools or MXToolbox can help verify these settings. When setting up your SPF record, make sure it includes all platforms your AI SDR will use, while staying under the 10 DNS lookup limit [22].

Next, evaluate your domain separation strategy. Using a dedicated secondary domain (e.g., outbound.company.com) can help safeguard the reputation of your primary domain.

It’s also crucial to examine your mailbox health metrics. Aim to keep your bounce rate between 1–3%, spam complaint rate below 0.08%, and unique open rates above 30–40%. If your metrics fall short, clean up your contact lists by removing inactive, unverified, or role-based email addresses (like info@ or sales@). Address any issues immediately to protect your deliverability. Additionally, use blacklist checkers, such as Spamhaus, to monitor your IP reputation. If you send more than 50,000 emails per month, consider switching to a dedicated IP for better control. Keep in mind that a dedicated IP requires a 2–4 week warmup period [18].

"The technical decisions you make today will impact your deliverability, reputation, and ultimately your campaign results for months or years to come."
– LeadsMagic [2]

Mailbox Warmup Strategies

Once your audit is complete, begin warming up your mailbox to establish trust with email providers. This involves gradually increasing email volume while fostering positive engagement signals [19]. Start by sending 10–15 emails per day to engaged recipients. Increase your daily volume by only 10–20% per week, ensuring that health metrics like bounce rates and spam complaints stay low.

For example, during the first week, send 10 emails per day. If performance metrics remain strong, increase to 15–25 emails per day in the second week. By the third week, introduce a small amount of cold outreach, and by the fourth week, balance your cold email volume to match your warmup volume at a 1:1 ratio [19].

Distribute your email sends throughout business hours instead of sending them all at once. For instance, if sending 200 emails in a day, spread them between 8:00 AM and 5:00 PM rather than sending them all at 9:00 AM. This approach helps avoid the appearance of automation.

Modern warmup tools, like Instantly.ai (starting at $37/month), can simplify the process by simulating real user behavior - such as scrolling, starring emails, and replying - helping to build trust with mailbox providers [20].

Keep your warmup process ongoing, even after reaching your target email volume. Gabriel Martínez, Founder of Reachflow, emphasizes:

"Even when your domains are performing well, you should never stop warming up the mailboxes... It's basically an insurance policy for your inbox placement." [4]

If a domain goes unused for 30 days or more, you’ll need to re-warm it entirely. Consistent warmup efforts ensure a strong deliverability foundation, which is critical for the success of your AI SDR campaigns.

Managing Email Infrastructure Over Time

Setting up your email infrastructure is just the beginning. To ensure your emails consistently land in inboxes, you need to monitor performance and address issues as they arise. While average B2B delivery rates in 2025 are around 98.16%, the actual inbox placement rate is closer to 85%. That means 15% of emails either get flagged as spam or blocked entirely - an issue that requires ongoing attention [24].

Real-Time Monitoring Tools

AI-powered SDR systems are invaluable for tracking key metrics like open rates, click-through rates, bounces, and spam complaints [23]. For example, Google Postmaster Tools provides daily updates on spam rates and domain reputation, offering insights into how Gmail views your email activity [5]. To go further, MXToolbox constantly scans blacklist databases and alerts you immediately if your IP is flagged, allowing you to reroute traffic and keep campaigns running smoothly [23].

Another tool, Masterbox, aggregates replies and engagement data from multiple mailboxes into a single dashboard. At a cost of $7–$9 per workspace per month, this setup allows AI SDR teams to identify patterns and address potential deliverability issues before they escalate [23].

AI-driven systems also play a critical role in resolving problems. They can detect reputation issues and automatically redirect traffic to higher-performing IPs or pause campaigns on underperforming domains. This "self-healing" capability ensures your outreach efforts continue uninterrupted while the system works to resolve the underlying issues in the background [23].

Responding to Deliverability Issues

When monitoring tools flag a problem, quick action is crucial. Email providers generally tolerate spam complaint rates under 0.1%, but going over 0.3% can trigger aggressive filtering [3][5][10]. If your complaint rate spikes, stop sending immediately and focus on recent engagers - those who interacted with your emails in the last 30–60 days - while your domain recovers [26].

Blacklisting requires a different approach. Use tools like MXToolbox to identify which blacklists you're on and pinpoint the cause. Common culprits include hitting spam traps or sudden increases in email volume. Address these issues before requesting removal from the blacklist [25][7]. During this recovery period, AI systems can reroute traffic through backup IPs to keep your campaigns active [23].

If inbox placement rates drop, start by reviewing your email authentication. Fully authenticated B2B senders are 2.7 times more likely to reach inboxes than those without proper authentication [3][10][24]. Ensure your domain is configured with SPF, DKIM, and DMARC. If authentication checks out, review your sending patterns - sudden spikes in email volume often raise red flags with ISPs [18][8].

"If your SDR team lives or dies by cold email, SPF, DKIM, and DMARC aren't an IT checklist - they're revenue infrastructure."
– SalesHive [3]

Spam complaints should be treated as a critical performance metric. If a specific sequence or sales rep exceeds a 0.1% complaint rate, pause their activity immediately to protect your domain's reputation. Regular health reviews should include checks on SPF/DKIM pass rates, DMARC alignment, and domain reputation trends, alongside your standard sales metrics [3][10]. By staying proactive, you can catch and resolve issues before they turn into major deliverability problems.

Conclusion

Your email infrastructure isn't just a behind-the-scenes detail - it's the backbone of your revenue strategy [3]. Without proper domain authentication, effective IP reputation management, and smart throttling strategies, even the most advanced AI SDR emails might never reach their audience. When infrastructure is prioritized, inbox placement rates can soar above 90%. On the flip side, neglecting it can cause those rates to plummet below 50% in just 3–6 months [1].

Achieving success starts with preparation, active monitoring, and long-term upkeep. Begin by auditing your current setup and implementing essential protocols like SPF, DKIM, and DMARC [3]. Take time to properly warm up your mailboxes over 4–8 weeks, and spread your email volume across multiple addresses to avoid bottlenecks.

Once the foundation is built, consistent monitoring becomes the key to maintaining success. Treat deliverability as a critical revenue metric. Weekly checks on spam complaints, domain reputation, and authentication rates are non-negotiable - especially when 45% of global email traffic is flagged as spam [3]. Staying proactive ensures your emails land where they’re supposed to.

AI SDRs perform best when supported by a scalable and reliable infrastructure. Whether you’re sending 1,000 emails or 100,000 each month, having the right domains, inboxes, and monitoring tools makes all the difference. If you're looking to align your technical needs with the right tools, check out AI SDR Shop (https://aisdr.shop) for tailored solutions.

The takeaway? Infrastructure amplifies outreach performance [17]. Fixing technical issues yields better results than simply refining your email copy - because even the most persuasive message means nothing if it never reaches the inbox.

FAQs

How do SPF, DKIM, and DMARC help improve email deliverability?

SPF, DKIM, and DMARC are key protocols that help ensure your emails reach their intended audience by verifying the legitimacy of the sender's domain. Together, they act as a shield against spoofing and phishing attempts, reducing the chances of your messages being flagged as spam.

• SPF (Sender Policy Framework): Confirms that emails are sent from servers authorized by your domain.

• DKIM (DomainKeys Identified Mail): Uses a digital signature to confirm the email’s content hasn’t been tampered with.

• DMARC (Domain-based Message Authentication, Reporting, and Conformance): Tells email servers what to do with messages that fail SPF or DKIM checks. Using these protocols not only protects your domain but also increases trust with email providers, boosting the likelihood that your messages will land in inboxes instead of spam folders.

What’s the difference between using a shared IP address and a dedicated IP address for email sending?

When using a shared IP address, multiple senders rely on the same IP. This means the reputation of that IP is shaped by the collective behavior of everyone using it. If even one sender adopts poor email practices, it can hurt the email deliverability for all others sharing that IP. On the other hand, a dedicated IP address is exclusively assigned to a single sender. This gives you complete control over its reputation, as only your email practices influence its standing. While this setup can lead to improved email deliverability, it does come with the responsibility of building and maintaining a strong reputation on your own.

Why is email throttling crucial for AI SDRs?

Email throttling plays a crucial role for AI SDRs by controlling the speed at which emails are sent. This measured approach helps avoid triggering spam filters, protecting your sender reputation and boosting the chances of your emails landing in inboxes. As email providers continue to tighten their filtering systems and rely heavily on engagement-based metrics, throttling becomes a smart way to keep your campaigns safe. It ensures your messages are delivered effectively without raising red flags.