An email service provider (ESP) offers email marketing services to businesses which have high volume email requirements, normally for marketing and/or transactional messages.

As well as literal email handling and fulfilment (including SMTP services or similar), most ESP’s offer software to enable marketers to manage email campaigns and subscribers, as well as reporting, optimisation and marketing automation functionality. Normally such software is available as a hosted service, although some providers do offer installed or “on-premise” solutions.

Email service providers often offer ancillary services such as design, testing, sender reputation and deliverability management.

Many enterprise marketing management or marketing cloud suites offer email marketing capabilities.