In what way? In all the documentation I’ve seen, it shows exactly how and where to put the API key and/or what kind of headers are required for that endpoint.

I think what I want to do is to generate a timestamp & HMAC on the Klaviyo side, that I can then consume in my app.

Similarly to this: https://api.slack.com/authentication/verifying-requests-from-slack

Hi @abr!

Just adding the link to the docs that @DavidSandel mentioned:

• How to add a webhook action to a flow

As far as sending additional information, as of now you can include Properties, Event Variables, and Django Logic - so you may be able to use some combination of those to formulate a webhook action that’s similar to the one you referenced.

I hope this helps!

- Brian