Sent immediately after a user joins the waitlist. Confirms the action and sets expectations.
Confirms what the user just did, names the product, gives a soft ETA, and avoids any marketing pretense. The job is to not lose trust before you have earned it.
Plain text. One sentence per paragraph. Sign it from a real person. Mention what they will hear about and roughly when.
Skip the long backstory, the founder vision essay, the unsolicited social-proof links. They opted in for a wait, not a pitch.