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ESP Defined

An ESP is an Email Service Provider. An ESP is a business solution that hosts email services and software on independent servers. ESP empower other businesses to send email campaigns to their email subscribers.

Using an email service provider is a low-cost and relatively unobtrusive way to reach your audience with a variety of marketing content. The most common types of marketing campaigns sent via email service providers include transactional updates, weekly newsletters, and seasonal promotions, all designed to keep your brand top-of-inbox and top-of-mind.

How to Use it in a Sentence

Partnering with an email service provider allows businesses to build a loyal following and regularly communicate with their customers at scale.

Common ESP FAQs

Popular email service providers include MailChimp, SendGrid, and Mailchimp.

OneSignal partners with best-in-class email service providers including SendGrid, Mailgun, and Mailchimp so that our customers can manage their email marketing and create dynamic cross-channel messaging campaigns, all from a single dashboard. If you’re new to email, we can manage the backend ESP setup so you don’t have to, or you can integrate your existing SendGrid, Mailgun, or Mailchimp account with your OneSignal account. With our intuitive drag-and-drop email templates, it’s easy to create high-quality branded emails without any design experience.

While small businesses can get away with independently managing their email lists, a growing user base ultimately requires the infrastructure of a professional email service provider. These services allow you several unique features, including:

  • Email automation

  • Pre-made templates

  • Audience segmentation

  • Unique lead capture forms

  • Detailed engagement and sales analytics


For example, OneSignal’s email marketing automation software unlocks everything from template-base email creation to an intuitive audience segmentation editor, to powerful, time-based automation triggers… all while optimizing your other cross-channel messaging.

Partnering with an established email service provider gives businesses user messaging capabilities that have been proven to boost sales, customer engagement, retention, and ad increase ROI (email marketing returns an average of $40 per $1 spent)!

Additionally, email marketing is one of the most historically effective forms of engaging customers. People are already accustomed to checking their email for promotions and updates from their favorite brands, meaning their inbox is often the first place they will check to hear what’s new with your brand.