SMS Marketing is the text messaging channel within Constant Contact's digital marketing suite. A business builds and maintains an opted-in subscriber list, then sends one-off or scheduled text campaigns and automated texts triggered by a customer action such as a signup or a purchase. Messages draw on the same campaign tooling as the email channel, including a link shortener, a dedicated sending number, and sign-up pages for collecting consent.

The service is sold as a monthly add-on to a Constant Contact email plan and is priced independently of that plan, so it cannot be bought on its own; Premium plans include a monthly message allowance. It is offered to United States customers who hold a valid tax or employer identification number, and it shares the account's contact list, segmentation, and reporting with the email channel. It is aimed at small business and nonprofit marketers who want a second direct channel alongside email.