What it does

Customer.io identifies people, tracks events, and sends transactional emails. Uses two different auth schemes — Track API (Basic) for identify/track and App API (Bearer) for transactional sends.

Setup

In Customer.io → Settings → Account Settings → API Credentials, copy Site ID + Tracking API Key, and optionally an App API Key.
In FlowFn, go to Platform Tools → Customer.io → Connect and provide site_id, api_key (track), app_api_key (optional), region.

Actions

Identify Person, Track Event
Send Transactional Email — requires App API key + a configured transactional message template