How Marketing Agencies Can Improve Email Deliverability at Scale

michael73507
May 2
3 min read

For marketing agencies managing multiple brands, clients, or campaigns, email deliverability isn’t just a technical detail—it’s the backbone of every successful email marketing effort. Poor deliverability means messages never reach the inbox, reducing engagement, conversions, and ultimately ROI.

When agencies are sending emails at scale—often across different ESPs and domains—the risk of landing in spam folders multiplies. But with the right strategies in place, deliverability can be protected, optimized, and turned into a competitive advantage.

Here are three core areas where agencies can improve email deliverability at scale: warm-up strategies, email authentication protocols (SPF, DKIM, and DMARC), and effective suppression list management.

1. Warming Up IPs and Domains the Right Way

New or “cold” IP addresses and domains are flagged by inbox providers as risky. To avoid getting caught in spam traps, every sender must build a positive reputation gradually—a process known as warming up.

What Is Warm-Up?

Warm-up is the process of gradually increasing the volume of emails sent from a new domain or IP address over time. This signals to ISPs that you’re a legitimate sender.

Best Practices for Agencies:

Start small: Send emails to your most engaged recipients first. These contacts are more likely to open and click, helping establish trust with ISPs.
Ramp gradually: Increase volume incrementally each day or week. EmailElement users can automate this process with rules-based send thresholds.
Use segmentation: Focus early sends on active segments—users who have recently opened or clicked.
Monitor performance: Use your reporting dashboard to track bounces, open rates, and spam complaints during the warm-up phase.

By warming up thoughtfully, agencies help new clients or campaigns get off to a strong start—protecting reputation and inbox placement.

2. Implementing Email Authentication Protocols

Email authentication is critical for proving your identity as a sender. Without it, your messages are more likely to be flagged as spam or spoofed by bad actors.

Here’s what every agency should set up for each client domain:

SPF (Sender Policy Framework)

SPF records specify which IP addresses are authorized to send email for your domain. It helps prevent domain spoofing but needs to be updated any time you add new sending services.

DKIM (DomainKeys Identified Mail)

DKIM adds a cryptographic signature to your email headers, verifying that the email wasn’t altered in transit and that it came from a trusted source.

DMARC (Domain-based Message Authentication, Reporting, and Conformance)

DMARC builds on SPF and DKIM by giving inbox providers guidance on what to do if authentication fails. It also provides reporting for visibility into who is using your domain.

Pro tip for agencies: Use a central platform like EmailElement to manage and validate authentication across all your clients' domains in one place. This saves hours of back-and-forth with IT teams and helps prevent costly misconfigurations.

3. Suppression List Management for Cleaner Sends

Suppression lists are often overlooked—but they’re essential for maintaining good sender reputation.

What’s a suppression list?

It’s a list of email addresses that should not receive your campaigns—either because they unsubscribed, bounced previously, or flagged you as spam.

Why It Matters at Scale:

When agencies send high volumes of email across multiple brands or ESPs, it’s easy for suppression data to get siloed. That means an unsubscribed user on one list might accidentally get emailed from another—leading to complaints, poor deliverability, or even blacklisting.

Agency-Specific Suppression Strategies:

Centralize suppression: Use a master suppression list across all brands and ESPs with EmailElement’s built-in suppression tools.
Automate updates: Ensure suppressions are applied in real time, especially for transactional or triggered sends.
Encrypt suppression data: Protect your list integrity by encrypting links and email data where appropriate—especially important for agencies handling sensitive customer data.

Make Deliverability a Strategic Asset

For marketing agencies, high deliverability isn’t just about technical hygiene—it’s about performance at scale. Better deliverability means more inboxes reached, more engagement, and more value delivered to clients.

EmailElement helps agencies automate these best practices—handling warm-up schedules, domain authentication, and suppression management—all from a centralized dashboard. Whether you're onboarding new clients or scaling seasonal campaigns, you’ll have the tools to protect your sender reputation and maximize impact.