Get one campaign's email numbers: sent, delivered, opened, clicked, unsubscribed, failed, with rates. The totals cover the campaign's life unless you send start_date/end_date; the daily series always covers the last 7 days. Test sends are counted separately in tests_sent.

Prerequisites: a bearer token and the campaign's id (campaignId). Optional: a window (start_date, end_date, both Y-m-d).

Authentication: Account token. The campaign must belong to the caller's own company; otherwise 404.

Rate limit: 120 requests per minute, counted per user (the token’s user).