• Case Studies

Bringing Professionals Closer To Their Dream Job With Transactional Email

Mailgun Team
5 min read

For a global job site like Quantum Response Network, sustaining high email throughput and generating return traffic to their websites is an important measure of success and profitability. With over one million active users in key markets such as the UK, the US, Canada, Australia, South Africa, India, Singapore, and the United Arab Emirates, Quantum Response Network needed a reliable Email Service Provider (ESP) to partner with and grow their business. To gain market share in the Online Recruitment space, Quantum Response Network was looking for the right infrastructure fit that could process and send over 1.2 million daily marketing emails around the clock.


Quantum Response Network needed to scale their infrastructure capabilities as their business grew year-over-year. While their daily sending volume continued to increase, their previous partner could not keep up with the incremental growth. They wanted to be proactive and understand what they could do better on their side to mitigate volume-related issues. The goal was to reach sending capacity of 1.5 million daily emails, and it wasn’t something they could do if they stuck to the same sending infrastructure.

Quantum Response Network had a simple sending infrastructure that would run email activity through 3 different top-level domains: each with at least 6 subdomains that had different mailing streams. It was barely enough to balance the heavy load of transactional emails sent to welcome subscribers and send them daily marketing emails. That’s when they decided to evaluate other ESP options, and they narrowed down the search to Mailgun, Mailjet, and SendGrid.

“Our previous partner was having serious issues coping with the volume of emails that we send out each day. We also felt that we didn’t have a clear idea of where we stood with our deliverability.” Graham Everitt, Director Quantum Response Network


With help from Mailgun, Quantum Response Network developed an infrastructure strategy that would provide higher visibility into email delivery. They began to build their sending reputation gradually using dedicated IPs tied to their domains, and balanced the load using shared IP resources to send over 1.2 million emails per day. Quantum Response Network integrated the Mailgun email API and made improvements to their infrastructure, working with a dedicated Technical Account Manager to maximize deliverability performance.

“…we found that Mailgun’s API could cope with any volume that we could throw at it. What was taking our previous partner 29 hours to send took Mailgun fewer than 2 hours.”

Through separation and aggregation of over and underperforming mail streams, they found that Quantum Response Network was able to send email faster than their system could generate transactional email. Mailgun provided the email know-how and best practices that Quantum Response Network used to solve for the high-volume constraints they had experienced before.


By using Mailgun’s shared IP resources, Quantum Response Network was able to lift the email sending performance of their key subdomains, and use best practices to sustain improved performance and deliverability. They can now measure and manage the impact of email delivery on their business. As a result, Quantum Response Network experienced a 95% increase in email sessions that have led to recurring web traffic to their page, and 1350% increase in sending speed for transactional email messages.

“Deliverability doesn’t need to be a silent killer, though it was to us previously…this doesn’t mean we feel that we have perfect deliverability as there isn’t such a thing, but we feel that by working alongside Mailgun we have the ex-pertise required to manage it as well as is possible.”

About Mailgun

A Y-Combinator success story, Mailgun is an email delivery engine created by developers for developers. Since 2010, Mailgun has provided deliverability expertise and leading technology via cloud-based email APIs for customers such as Slack, Github, and Shopify. Through its own proprietary technology, Mailgun strives to continuously ensure you can send, receive, and track email effortlessly.

Last updated on September 23, 2019

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