Split-test results per variant

GET /api/v2/emails/broadcasts/{broadcast_id}/stats?expand[]=variants now breaks a split test's numbers down by variant: recipients, unique clicks, unsubscribes, spam complaints and bounces, with the test itself kept apart from the winner's send to the rest of the list. Until now the only per-variant number was opens, and privacy features in mail apps inflate opens enough that they rarely settle which subject line actually worked.

Clicks and unsubscribes are the honest signal. Comparing variants on the test alone, rather than on totals the winner's bigger send would swamp, tells you which subject and preview text earned the click and which one cost you subscribers.

Agent examples: pick split-test winners on clicks instead of opens · track which subject lines drive unsubscribes · build a running log of tested subject lines and their results

Resources: Fetch Email Broadcast Stats · Emails::Broadcast. Building with an AI agent? Point it at the Emails skill.