Hi @Care_P and welcome to the Community!

These use cases can certainly be accomplished using API-based Transactional Events, as discussed in this Developer Portal Article. We recommend using the server-side Track API to send transactional events, since it’s a safer, more reliable method of transmission than the JavaScript Track API which can be blocked by someone’s browser or device.

For the “Forgot Password” email, you can follow the instructions included in the guide, where there’s an example of what the Reset Password payload should look like:

• Reset Password

For OTP verification, you may need to use a third-party tool to generate OTP codes that can be integrated with Klaviyo. Either that, or you will have to use a custom metric to pass the PTO from your password verification tool into a variable in an email:

Customer requests OTP (via button/link) > Custom Metric fires that includes generated OTP > Flow is triggered by custom metric > customer receives flow email that includes OTP as an event variable.

Here’s the Developer Guide on creating custom events:

https://developers.klaviyo.com/en/v1-2/docs/custom-event-tracking

If you would like more in-depth help with custom development, you’re always welcome to reach out to one of our incredible Official Partners!

I hope this helps get you started, and thanks for using the Community!

-Brian