Start Email Flow From a Trigger From API

The simple solution:

1. fire a custom event via the api
2. Setup a flow that triggers off of the event which immediately sends the first email
3. flow should have a time delay and then the second email
4. another time delay and then the second email

I’d be sure to add a flow filter that checks to make sure the customer hasn’t already renewed their subscription. That could be identified by either another event or a profile property. Flow filters are checked before EACH email, so you only need to set that up once.

A case that you might want to think about, and a slightly different solution

If you already have customers in the trial before you’re launching this flow. Their trial is going to expire in less than 30 days. You could set the initial email on it’s own and trigger the reminder emails based on the expiration date:

1. store the expiration date as a profile property
2. trigger the flow based on X days before the expiration date
3. time delay and then the final email

The benefit of this solution is that you can set the expiration date 2 ways:

1. When sending the “trial start” event that triggers the first email, include the expiration date as a profile property
2. Set the profile property independently via the API or an SFTP upload to handle

You could also handle the “customer has already renewed” case by just deleting the expiration date profile property.