An autoresponder is an email — or a short series — sent automatically in response to a specific trigger, such as a signup confirmation or a thank-you after a purchase.
In depth
The autoresponder is the simplest building block of automation: one message (or a small sequence) tied to a single event. More elaborate workflows chain several autoresponders together with conditions and delays.
Example
A double opt-in confirmation email sent the instant someone subscribes. Welcome autoresponders average a 35.53% open rate, far above typical campaign sends (Omnisend 2025).
Related terms
Explore autoresponders in our email marketing automation guide.