ESP Matching | Get More Leads with Better Deliverability

Sending emails is like throwing a message into the ocean in a bottle. You hope it gets to the right person, but sometimes it just disappears. In these situations, ESP matching can help you.

ESP matching can help your emails get delivered straight to inboxes instead of the spam folder.  

In this article, you will get to know all about ESP matching, its benefits, use-cases and how it can be used in complement with inbox rotation.

What is ESP matching?

what is ESP matching

Let’s say you’re running a cold email campaign. Traditionally, all emails would be sent from the same source, regardless of your recipient’s email service provider (Gmail, Outlook, etc.).

ESP matching takes it a step further. It analyzes your recipient list and identifies the Email Service Provider (ESP) they use based on their email address (e.g., Gmail address for someone with an address). Then, it prioritizes sending emails through matching ESPs. So, ideally, an email sent to a Gmail address would come from a server that also handles Gmail accounts.

This approach aims to mimic regular email flow and make your emails seem more legitimate. Email providers are more likely to trust and deliver emails that appear to come from familiar sources.

Recommended Read: What is Inbox Rotation? Will unlimited sending emails help?

How does ESP matching help with email deliverability?

Cold outreach campaigns rely heavily on email deliverability to reach potential customers. 

ESP matching can significantly improve your chances of landing those emails in inboxes  for a few key reasons:

✅ Regular email flow

Cold emails can sometimes raise red flags for email providers because they come from a sender the recipient doesn’t know. ESP matching helps by making your outreach appear more natural. 

When you send an email through the same ESP the recipient uses (e.g., Gmail to Gmail), it looks like a regular email exchange. 

This familiarity increases trust with the email provider and reduces the likelihood of your email being flagged as spam.

✅ Bypassing spam filters

Email providers use powerful algorithms to filter spam. These algorithms look for patterns that might indicate bulk or unsolicited emails. ESP matching disrupts these patterns. 

By sending emails through various ESPs, your campaign avoids triggering spam filters that might be looking for a high volume of emails from a single source.

✅ Building Sender Reputation 

Every email sender has a reputation score with different ESPs. This score is based on factors like bounce rates, spam complaints, and engagement. Sending emails through matching ESPs can help build a positive sender reputation with those specific providers. This, in turn, improves deliverability for future emails sent through those same ESPs.

How is ESP matching useful?

ESP matching provides several benefits, which include email deliverability. 

Since we have already discussed email deliverability, we shall now check how ESP matching helps with an increase in email efficiency. 

✔️ Effortless Optimization

ESP matching automates the entire process. You don’t need to spend time manually segmenting your list or figuring out which ESP to use for each recipient. 

The tool handles it all for you, freeing you up to focus on crafting compelling emails and managing your campaign.

✔️ Scalability

ESP matching is particularly useful for large-scale email campaigns. It ensures consistent delivery rates even when sending a high volume of emails.

✔️ Improved Resource Allocation

ESP matching helps you allocate resources more effectively. You don’t need to invest time or money in researching and implementing complex email-sending strategies for different ESPs.

✔️ Simplified Campaign Management

With ESP matching, you can manage your entire email campaign from a single platform. This eliminates the need to track and monitor multiple campaigns across different ESPs, reducing complexity and streamlining your workflow.

✔️ Reduced Risk of Errors

Manually configuring email sends for different ESPs can be prone to errors. ESP matching automates the process, minimizing the risk of mistakes that could potentially impact deliverability or campaign performance.

✔️ Consistency Across Campaigns

ESP matching ensures consistent sending practices across all your email campaigns. This helps maintain a positive sender reputation with all major ESPs, leading to overall better deliverability in the long run.

esp matching

ESP matching – use cases

To grasp the concept of ESP matching more clearly, let me illustrate it through various practical scenarios.

Cold outreach campaigns

Challenge: In B2B cold outreach, reaching the right decision-makers within target companies can be difficult. Emails often get flagged as spam due to unfamiliar sender addresses and generic content.

Solution: ESP matching helps emails appear more legitimate by sending them through the recipient’s likely ESP (e.g., Gmail for a personal email address). This increases trust with the email provider and reduces the chances of being filtered as spam.

Benefit: Higher email deliverability leads to more potential customers seeing your outreach message, increasing the likelihood of starting conversations and generating leads.

Account-Based Marketing (ABM)

Challenge: ABM targets high-value accounts, and reaching the right individuals within those accounts is crucial. Generic outreach tactics might get lost in the noise.

Solution: ESP matching allows for more targeted communication. By sending emails through the ESP used by the specific domain of the target decision-maker (e.g., sending to someone at a company that uses Microsoft Exchange), you can potentially bypass spam filters associated with bulk marketing emails and increase the chances of your message getting noticed.

Benefit: Increased chances of your message getting noticed by key decision-makers within target accounts, leading to better engagement and potentially closing more deals.

Partner Marketing Campaigns

Challenge: Coordinating email marketing efforts with partners can be complex, and there’s a risk of emails getting flagged as spam when sent from a different domain.

Solution: ESP matching facilitates smoother communication and potentially improves deliverability. By sending emails through the partner’s preferred ESP, you leverage their established sender reputation and increase the chance of your message landing in the inboxes of their audience.

Benefits: Better campaign execution, improved partner collaboration, and potentially higher engagement with the target audience.

Event Registration Follow-Ups

Challenge: Following up with webinar or event registrants often involves sending a high volume of emails, which can trigger spam filters.

Solution: ESP matching helps personalize follow-up emails. By sending emails through the attendee’s ESP, you can potentially improve open rates. Additionally, personalized content based on the attendee’s interests (assuming the ESP integrates with your marketing automation platform) can further increase engagement.

Benefits: Higher open rates for follow-up emails, increased engagement with post-event content, and potentially more qualified leads generated from the event.

How can ESP matching be used with Inbox rotation?

Before we go ahead to discuss how ESP matching and inbox rotation can be complementary outreach strategies, first let me explain about inbox rotation. 

Normally, you send emails from just one inbox.  With inbox rotation, you connect multiple inboxes in a single email campaign. Email providers have limits on how many emails you can send from a single account each day. With help of inbox rotation, you spread your emails out over multiple addresses. 

With inbox rotation, you are less likely to hit those limits and get flagged as spam. It helps to maintain a positive domain reputation. 

When you use ESP matching and inbox together, it can significantly improve the deliverability and effectiveness of your B2B email campaigns. Let’s see how.

Segmented sending

ESP matching automatically sorts your email list based on the recipient’s email service provider (ESP).  For each group, emails are then distributed evenly across multiple email addresses within your inbox rotation pool. 

This ensures you get the benefits of ESP matching (higher deliverability) while maintaining a healthy sending reputation by automatically balancing the workload.

Warming up of new email address

When adding new addresses to your inbox rotation pool, it’s crucial to “warm them up” by sending a low volume of emails initially. ESP matching can be helpful during this process. 

By sending emails through matching ESPs for the new addresses, you can gradually build a positive sender reputation more quickly. 

Building a sender’s reputation

Over time, consistently using ESP matching and inbox rotation can help build a pool of sending addresses with positive sender reputations across different ESPs. 

This provides more flexibility in campaign execution and allows you to scale your email marketing efforts more effectively.

Recommended Read: Google & Yahoo’s New Email Sender Policy 2024

How does ESP Matching? is a sales engagement platform that automates and optimizes communication across multiple channels. 

It goes beyond just email automation, allowing you to design and schedule multichannel outreach campaigns that include email, LinkedIn interactions, WhatsApp messages, calls, and texts. boasts features like automated & semi-automated LinkedIn outreach sequences, inbox rotation to improve email deliverability, and a powerful scheduler to ensure emails land in your prospects’ inboxes at optimal times. Smartreach provides unlimited sending email addresses within a single campaign with it’s inbox rotation feature.

SmartReach provides AI-generated email content that helps to hyper-personalize your content based on your target audience. 

It also streamlines collaboration with a shared inbox for your sales team and closes more deals. 

SmartReach is soon going to introduce ESP matching feature. Post which ESP matching along with inbox rotation can prove to be a very powerful tool for your cold outreach.


ESP matching can prove to be a big boon for your email outreach efforts. By considering the recipient’s email service provider, you can increase your chances of landing in their inbox instead of the spam folder. This is especially useful for cold outreach campaigns and ABM (Account-Based Marketing), where reaching the right person is critical.

ESP matching can be even more powerful when used together with inbox rotation. Inbox rotation lets you distribute your emails across multiple inboxes to avoid hitting sending limits and getting flagged as spam. 

When you combine this with ESP matching, you get the benefit of both worlds: increased deliverability and a healthy sending reputation.

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