---
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"@id": https://www.twilio.com/docs/glossary/mailbox-provider#article
headline: Mailbox provider
description: "*Marketing*. A service organization that provides transactional email services, marketing email services, or both."
url: https://www.twilio.com/docs/glossary/mailbox-provider
inLanguage: en
dateModified: 2026-05-06T13:22:30.000Z
author:
  "@type": Organization
  name: Twilio Developer Education Team
publisher:
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  name: Twilio
---

# Mailbox provider

*Marketing*. A service organization that provides transactional email services, marketing email services, or both.

This is also known as an mailbox provider, mail service provider or [Email Service Provider (ESP)][esp].

Twilio SendGrid is an example of a mailbox provider.

[esp]: /docs/glossary/email-service-provider