Making the Choice: On-Prem or ESPs?


In June of this year, we were in Prague as one of the proud sponsors of the Deliverability Summit. We also took part in a great panel discussion Expert Advice from Alice Cornell, Steve Tuck of Halon, Matthew Grove of Mailchimp and our own Maarten Oelering. The discussion focussed on owning your email infrastructure.

Developing your own email infrastructure can offer considerable benefits for some businesses. By assuming full operational control, companies can have better visibility into email delivery issues and devise tailored solutions to enhance performance. However, it's crucial to remember that with increased control comes greater responsibility, which includes managing system failures, ensuring high availability, and maintaining a positive IP reputation. It is not for everyone!


"Don't forget that with an ESP, you're paying for constant upgrades, maintenance, and attention. It's about more than just the initial sticker price. You need experts who know all the hidden variables to solve your email infrastructure problems." Maarten Oelering


In this panel discussion, you will be able to:

  • Get a holistic picture of the pros and cons involved in setting up your own email infrastructure.
  • Find your footing when deciding between on-premise solutions and Email Service Providers, laying out a road map for your choices.
  • Prepare yourself for system failures and secure high availability, turning unexpected interruptions into planned strategies.
  • Navigate a little better the differences between open source and commercial Mail Transfer Agent systems, tailoring the best fit for your requirements.

Some key moments in this episode are:

00:01:10 - Definition of Terms: MTA, On Prem, SaaS
The panel discusses the definitions of terms like MTA (Message Transfer Agent), On Prem (on-premise infrastructure), and SaaS (Software as a Service). They explain the differences between operating your own email delivery infrastructure and using ESPs like SendGrid and Mailgun.

00:03:16 - Cost Considerations
The panel discusses the cost factors involved in setting up your own infrastructure versus using an ESP. They mention that while on premise infrastructure may have higher upfront costs, it could be more cost-effective in the long run. They also emphasize the importance of ongoing maintenance and expertise in maintaining your own infrastructure.

00:09:31 - Reasons for Choosing On Premise
The panel discusses the reasons why someone might choose to set up their own on-premise infrastructure, such as data sovereignty, tight integration with existing systems, and the ability to have full control over email domains and authentication methods.

00:12:14 - Transitioning to Owning Infrastructure
The panel shares their experiences and advice on transitioning from using ESPs to owning your own infrastructure. They highlight the importance of taking small steps and building expertise over time. Owning your own IP range can be a good first step, , but it's crucial to ..

00:20:00 - Planning for Infrastructure Failures,
Owning your own infrastructure requires careful planning for when things break. Implementing safety measures, such as backup systems and stop gaps, is crucial for managing email delivery and preventing issues like double sending or lost emails.

00:26:13 - Balancing Control and Expertise,
Companies that opt for on-premise infrastructure often believe they can achieve better delivery than third-party vendors. However, it requires a dedicated delivery team and extensive knowledge. ESPs also rely on third-party experts, highlighting the importance of community collaboration in improving email delivery.

00:35:21 - Main Differences Between Open Source and Commercial MTA Systems,

00:37:16 - Reasons to Choose a Commercial MTA,

00:38:41 - Challenges and Advantages of Open Source MTAS,
Open source MTAS like Postfix require proficiency in low-level programming languages and extensive modifications to handle high volume or multiple users. However, they can be heavily modified and offer fast solutions. Integration and working with SMTP can be challenging for developers who are more familiar with web technologies.

00:40:46 - Advantages of Commercial MTAS for Developers,

00:42:50 - Advice for Decision-Making,
The panel advises seeking help from the community and experts, as the email space is constantly evolving.


The advice mentioned in this session includes:

  • Consider the cost of setting up your own infrastructure versus using an ESP.
  • Hire a deliverability expert to help with maintaining and optimising your email delivery.
  • Understand the hidden variables and complexities involved in managing your own infrastructure.
  • Consider data sovereignty regulations and the need to keep data within certain borders.
  • Evaluate the benefits of owning your own IPS for long-term control and flexibility.
  • Seek advice from experts in the field to guide you through the decision-making process.

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