Changing of ESP? This is how to avoid disaster

There are quite some factors that have an influence on whether a marketer would want to change their ESP. It can be due diligence (such as looking for better pricing) or out of need (such as deliverability problems).

In all cases, changing an ESP is something one should care about and be well prepared for.

Stage one: Back-up your databases on a regular basis

By using an external marketing platform marketers are giving away valuable assets (like their contact list) to a third party. But if marketers exploit the sending infrastructure, they are likely to generate a great deal of data. To be one step ahead, it is important to get these databases backed up as often as possible. Marketers who have not done this since the start risk losing important data without the chance of getting it back.

Below is a list of all the information needed before changing the Email Service Provider:

  • All unsubscribes. It would be a useless task to start the communication process with the new ESP from scratch.
  • All data on bounces. Collect hard bounces (permanent errors) as well as soft bounces (temporary errors).
  • Spam reports. These are retrieved, when possible, from webmail providers and ISPs FBLs.
  • Historic data of all clicks and opens. This is a keystone asset in an email list. Aim to get at least the data from the last interaction date.
  • Quarantines and other suppression lists. Some senders install in-house rejecters deployed to block specific addresses when sending messages. Having this data at hand will be useful to analyze it, as well as to freshen up your list.

Stage two: Get familiar with your new ESP

The new platform will ask a wide range of questions related to the former sending practices. The answers will then be used to test the marketers practices and his reputation as a sender according to web mails ISP’s.

These questions may look like the following:

  • If working with dedicated IP addresses, which are these?
  • If taking part in a shared IP pool, what is the distribution employed by the other users in the pool? Which IP addresses are being used by this pool?
  • What are the domain names used to send your emails (FROM: field) as well as the ones used for link tracking?

Stage three: End your contract smoothly

It is very disappointing to see that companies neglect the switching progress when converting their email sending platforms. We must learn to walk before we can run: make sure the brand new platform is 100% operational before breaking up with the previous ESP. Being blocked out from the former databases and owning nothing but a half-operational brand new platform can easily turn into a never ending nightmare for the business.

Stage four: Reintegrate your databases and clean up

All the databases that have been collected during Stage one must be reintegrated into a fresh (in-house) hosted emailing list. Transferring these databases without changes would be useless.

It is imperative to make sure that:

  • Each unsubscribtion has been marked.
  • Hard bounces have been cleaned up.
  • Spam reports cannot be targeted again.
  • Inactive mailing lists have been set apart from databases. Ensuring that these have been transmitted to a specific marketing program. This is retrieved from the data on last interactions.

Stage five: Authentication set up

This is the first thing on the to-do list when setting up the new ESP. SPF and DKIM records configuration will provide the marketer with authentication and will give the new sender the power to send emails on their behalf.

Marketers should experience no problems if they decide to continue to send emails through their former sending platform. In this scenario, their SPF record can be used for simultaneously sending with several email platforms, enabling them to set several DKIM records on the same domain name.

Furthermore – even if it is not directly related to the authentication process – we encourage marketers to ask their new email service provider to use their sending name to customize the tracking links generated by such emails.

Stage six: Syncing data with your new ESP

So now that marketers have retrieved the databases from their old provider and freshened up the contact lists, it is time for contact syncing on their new sending platform.

Syncing is a two-way road. Marketers should send their mailing list to the new ESP to ensure that all items mentioned in Stage one can be automatically retrieved. If they do so, the upcoming migration processes will be carried out smoothly and more importantly – even if it happens in 5 years – they will remain the master of their assets.

Stage seven: Learn about the warm up phase

When marketers send their first emails from a new IP address, webmail providers and ISP’s have not yet had the chance to determine the marketer’s reputation. Therefore, their filters will be rather harsh during the first few weeks. To start building a trustworthy relationship with these filters, we recommend marketers ‘warm up’ their IP address by sending a constant email volume over a given period of time.

Stage eight: You’re not done!

Marketers have now achieved the “deliverability” migration stage. It is now time to once again deploy all the email marketing campaigns they own into their new platform. But that is a whole different story!

Jonathan Loriaux

About Jonathan Loriaux


Jonathan Loriaux is a blogger, speaker, expert in email marketing and founder of the european email marketing agency Badsender.

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