Trying to replace existing email service provider and consolidate


We are looking for some help for one of our clients who wants to migrate all of their marketing automation, analysis and customer communication, including newsletter blasts to Hubspot. The problem we are running into is that the client wants to use a mailing list kept at Hubspot but continue to format newsletters within our tools. With their current ESP integration, we send the formatted email through the ESP’s API to a mailing list (identified by ID). The ESP is the authority for this list. Ideally, the client wants to replicate this behavior at Hubspot.

Does anyone know how this can be accomplished? I have outlined all criteria below.

  • Our client uses our administration tools to create the HTML and Text versions of the email they want to distribute.
  • We transfer the formatted emails to the provider through their API.
  • At the same time, we tell the provider when to deliver the email and identify a list within the provider’s system that the email should blast to.
  • We’re not the master for our client’s email lists, as many times other subscribers are added to those lists by various means, without our knowledge. That information never makes it to our database.
  • Ultimately we’d like to opt subscribers in and out of those lists within Hubspot using a Hubspot API as well and allow clients to opt themselves out of some newsletters through an unsubscribe link pointing back to Hubspot.


Hi @integrator,

Sounds like the transactional email add on would be what you need. You can find more details on the add on and it’s functionality below:



Thanks for the reply. We looked at the transactional email information but it looks like emails need to be sent out by us one at a time. There may be 1200 emails or more in one send so individually sending each email is not really the right solution for us. Perhaps we are missing how this would work with the transactional API, but is it possible to pass an HTML message to Hubspot and have it sent to a list of users that is held and maintained at Hubspot?


Hi @integrator,

The transactional email add on is the only method by which you can pass externally built HTML emails to be sent via HubSpot. You could theoretically store the contact list in HubSpot, and use the contact lists API to pull the intended recipients before sending the email via the SMTP API.