Tutorial: trigger transactional emails from PostHog events with Mailtrap

Summary

Mailtrap already has a data warehouse source in the PostHog catalog, and we'd love to do a tutorial together.

The idea: a how-to on closing the email loop with PostHog. Fire a Mailtrap send when a PostHog event happens (welcome email on signup, a nudge on inactivity) using a webhook/CDP destination, then pull the per-email delivery, open, and click events back into PostHog through the existing source (they come through in email_logs, with timestamps and clicked URLs). Readers get the whole thing in one place, event to email to engagement, plus a copy-paste example.

The tracking side works today with the source as-is. The sending side works today via a generic webhook destination, and gets cleaner once the dedicated "Send email via Mailtrap" destination we proposed lands (https://github.com/PostHog/posthog/issues/83172). Happy to co-write or hand over a working example.

Label: blog / tutorial
Please add to Content & Docs project board

Headline options

• How to trigger transactional emails from PostHog events with Mailtrap
• Close the email loop in PostHog: send with Mailtrap, track opens and clicks
• Turn PostHog events into emails with Mailtrap

What (if any) keywords are we targeting?

A few fit, with monthly US search volume (per ahrefs):

• transactional email — 6,100
• email api — 700
• email testing — 500
• send email api — 250
• transactional email api — 250 (low difficulty, KD 7)
• posthog email — 20 (direct-intent, your users searching for exactly this)

The piece covers "sending and tracking transactional email," so it can lean toward whichever of these fits your content plan.

Outline (optional)

The loop: PostHog event to email to engagement data
Set up the Mailtrap data warehouse source
Send an email when an event fires (via webhook destination): signup, inactivity
Pull per-email delivery, opens, and clicks back into PostHog (from email_logs)
Build a simple dashboard tying email events to product behavior

Start by reviewing the existing Mailtrap data warehouse source, the generic webhook destination flow, and the email_logs data described in the issue. Produce the tutorial with a working event-to-email-to-engagement example, covering setup, delivery/open/click tracking, and a dashboard; note that the dedicated destination in issue 83172 is not yet available.