Unfortunately no but there are workarounds for at least a piece of what you need. What I did in my app was count how many things I had in my database before I started my API workflow. Let’s say there were 10. Then, I run a count on how many items I expect to get back from my API workflow using :count. Let’s say I’m expecting 40 items (you can do this BEFORE you run the workflow by the way). Once the count of the database is 50 (10 original items + 40 new ones), then I know I’m done… Now… Back to your original message, being able to send a message AFTER it’s done, that is where I’m not sure. You could set an item to show when it’s completed. Then when the item is visible, set “When X is visible” to send an email.
I wish I could go into more detail. Maybe that helps a bit?