What are the major mailbox providers globally?

The global mailbox provider landscape is dominated by a handful of major players. Gmail leads with over 1.8 billion users worldwide, making it the most influential MBP for deliverability. Microsoft (Outlook.com, Hotmail, Office 365) comes second with hundreds of millions of consumer and business accounts.

Yahoo (including AOL, which merged under Verizon Media) remains significant, especially in the United States. Apple iCloud serves the Apple ecosystem with growing market share. These four providers likely represent 80% or more of your typical B2C email list.

Regional providers matter too: GMX and Web.de dominate in Germany, Mail.ru leads in Russia, Yandex serves Russian speakers globally, and ProtonMail attracts privacy conscious users. Understanding which MBPs your audience uses helps you prioritize optimization efforts.