Email Infrastructure and Service Providers

30 Questions to Ask Your Next Email Service Provider

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Senders need email service providers (ESPs) like avocados need toast.  

After all, ESPs help senders create better designs, manage their subscriber lists, stay legally compliant, and measure results more effectively. 

But it’s normal for your needs to shift over time as your email program evolves.  

If you’re hitting roadblocks with your current email service provider (ESP) due to growing send volume, increase in mail streams, lack of functionality, or a poor support experience, it might be time to break up with your ESP and look elsewhere. 

Overwhelmed at the thought of shopping around? You’re not alone. 

With hundreds of ESPs on the market, all offering unique services and functionality, it can quickly become a daunting task. 

When interviewing potential options, it’s important to ensure the features and functionality offered will support your current needs and provide you with the support to grow your program over time.  

Luckily, you don’t need a sixth sense to choose the right ESP. Follow this checklist of questions when interviewing potential ESP partners to find the right fit. 

List management 

Even the smartest senders are only as good as the quality of their lists.

 ESPs offer a variety of features focused on helping senders maintain a clean and engaged list. Some questions to ask around this topic are: 

  • Do you allow personalization? 
  • How do you support client preference centers? 
  • Can you honor subscriber requests to reduce frequency of sends? 
  • Do you allow senders to customize the opt-out experience? 
  • Do you allow senders to manage and customize their opt-in page? 
  • Could we implement suppression rules that are unique to each mailbox provider? Or, do rules apply to all mailbox providers? 
  • Can we reduce send frequency for our lapsed subscribers? 
  • Can we have the flexibility to enable a single or double opt-in? 
  • Do we have control over how soft and hard bounces are handled? Can we choose to mail to addresses that we believe were falsely rejected? 

Reporting capabilities 

An ESP’s reporting capabilities can vastly differ across the board. To keep your team from being overwhelmed with information (or not having enough information), it’s important to decide which data points you and your team absolutely need, and which are just ‘nice to have’.  

Asking the questions below will help give you an idea of what to expect from an ESP’s reporting features: 

  • What would my dashboard look like when reviewing campaign performance? 
  • How do you display opens? Do you exclude Apple’s Mail Privacy Protection (MPP) opens or is this information all-inclusive of real and pixel opens? 
  • Do you provide real-time data reporting? 
  • How do we view our soft and hard bounces? Do we have access to bounce codes and reasons? 
  • Do you offer click-through and website conversion tracking? 
  • Will you share the number of emails sent, delivered, and not delivered? 
  • Do you have the ability to report on forwards? 
  • How will we be able to access data related to our unsubscribes and complaints? 
  • What feedback loops do you set up for your IPs? 
  • Are there any requirements to be integrated with a specific CRM system? 
  • How do you handle personally identifiable information (PII) and data privacy concerns? 

Email sending and scheduling 

Review your current sending processes and highlight areas that must stay consistent throughout an email service provider migration. For example, if you rely heavily on A/B testing or scheduling deployments, make sure these features are readily available and easy to use.  

Questions to ask here include: 

  • Can you walk us through the experience of setting up journeys? 
  • Do you allow emails to be throttled over several hours or days? 
  • Do you align with the connection and throughput settings mentioned here? 
  • Can we schedule sends for future dates/time? 
  • Do you support the use of dynamic content? 
  • Do you allow A/B split testing? If so, could you walk us through how you would set that up? 
  • Do you support triggered emails based on various methods of activity (or inactivity)? 

Creative and testing 

Some senders rely on ESPs to provide certain creative and email content testing tools prior to live deployments. If this is true of your program, you’ll want to ensure an ESP offers a competitive set of creative tools to help your emails make a splash. 

Questions to ask here include: 

  • Do you allow test emails to be sent to a small test group prior to live deployment? 
  • Can we create and edit email creatives directly in the user interface? 
  • Do you offer free, customizable email templates? 

Your team and support 

Fast, efficient service separates great ESPs from options that are just O.K. When vetting an ESP, take the time to ask questions about what their client experience looks like and how they handle support requests. 

Whether it be through a self-service or a full-service model, each email service provider should be able to provide you with details to ensure you will receive the support needed. 

Questions to ask here include: 

  • Will you assist in IP warming? How? 
  • Will I have a dedicated representative for questions, or will I submit questions via a ticket?
  • What is your support ticket turnaround time? 
  • Will we have a dedicated deliverability team? 
  • How many users will have access to the ESP interface? 

 Email infrastructure 

Infrastructure can have a huge impact on a sender’s deliverability. So, it’s critical to know if you’ll need to make any changes to your program’s current infrastructure.  

Your ESP’s answers should help you feel comfortable with any shifts you might have to make if you move forward. 

Questions to ask here include: 

  • Do you offer both dedicated and shared IPs? Are there any limitations to either?
  • Do you support DMARC, DKIM, and SPF? 
  • Do you manage complaint feedback loops? If so, which ones? 
  • Do you deploy alerts if there’s an issue with a certain complaint feedback loop or authentication? 

You’ve landed the perfect ESP—Now what? 

You can officially cross ‘find a new ESP’ off your to-do list. But that’s only half the battle. Your next step is managing a successful IP migration.  

This includes establishing a warmup plan for your program that protects your domain and IP reputation. Follow these tips to help ensure a successful migration: 

  1. Start small! Create a warmup plan that starts with a small daily send volume and grows slowly. You’ll want to avoid migrating all of your send volume in a short period of time. This can appear spammy to mailbox providers. 
  2. Focus on engagement. Your most engaged subscribers are the perfect segment to use when warming up your new IPs. The more engagement you can drive on these new IPs, the more confident mailbox providers will feel about delivering your emails to the inbox. 
  3. Be flexible. If you begin to see spam placement on your new IPs, slow down your warming plan for the mailbox provider in question, and see if they have a postmaster resource to help troubleshoot spam placement issues. 


Remember: Your choice of email service provider can either position your program for continued success and growth—or become a huge roadblock. 

Use these questions to ensure you end up with the right ESP and to kick off your new relationship on a positive note.  

Finding a new ESP and managing a successful migration is a time-intensive process, but will be rewarding when done properly.  

One final tip? It’s important to have your email deliverability in good standing so you can take full advantage of all your new ESP has to offer.  

To master the ins and outs of email deliverability, check out our “5 Minute Guide to Email Deliverability.”