We send one-time emails to contacts in Hubspot using a third-party application.
We can see the email sent by BCC'ing Hubspot, but we cant track email opens.
What's the best method: SMTP API or Single-send API?
We subscribe to "Marketing Hub Starter - Marketing Contacts" & "Legacy Sales Hub Professional". Were hoping it won't cost an extra 10k a year just to send the odd email to a few hundred contacts.