Overview of the most popular email clients

Overview of the most popular email clients

Email clients are the applications and platforms people use to read and manage email. From mobile apps to desktop programs and web browsers, each email client interprets message content slightly differently. For businesses that send email for marketing, notifications, and service communication, understanding client usage helps ensure messages render correctly and deliver a consistent experience.

This article provides an overview of the most popular email clients worldwide, explains how client usage affects email design and testing, and outlines why this is relevant for business communication.

The table below summarizes leading email clients based on global email open share.

Email clientApproximate share of email opens (global)
Apple Mail (iPhone, iPad, macOS)~56%
Gmail (Google)~32%
Outlook (Microsoft)~4%
Yahoo! Mail~2.5%
Other clients~5.5%

Sources: Litmus Email Analytics and Statista aggregated market data.

What an email client is

An email client is software that retrieves, displays, and sends email messages.

Clients may be:

  • Native applications installed on a device

  • Web-based interfaces accessed through a browser

  • Integrated tools within operating systems

Examples include Apple Mail, Gmail, Outlook, and Yahoo Mail. Each client handles HTML, images, fonts, and layout rules differently.

Why email client usage is relevant for businesses

Email client adoption varies by region, device, and user behavior. For businesses sending email campaigns, transactional messages, or service updates, client distribution influences how messages should be built and tested.

Key considerations include:

  • Which clients to prioritize during testing

  • How layouts render on mobile versus desktop

  • Feature support such as dark mode and fonts

Knowing which email clients your audience uses helps guide design and testing decisions.

Notes on leading email clients

  • Apple Mail leads globally due to default installation on Apple devices

  • Gmail is widely used across web and mobile environments

  • Outlook remains common in corporate and enterprise settings

  • Yahoo Mail maintains regional and legacy usage

  • Other clients include smaller regional and niche services

These figures represent aggregated analytics data. Actual distribution may vary by industry or audience.

How email client differences affect business email

Email clients differ in how they render HTML and CSS.

These differences affect:

  1. Layout consistency

  2. Image handling

  3. Font support

  4. Button behavior

  5. Dark mode presentation

Testing across major clients helps prevent visual or functional issues from reaching recipients.

Testing and optimization across email clients

Recommended practices include:

  • Prioritizing Apple Mail, Gmail, and Outlook during testing

  • Reviewing both mobile and desktop views

  • Verifying images, links, and fallback styles

  • Checking dark mode behavior

  • Reviewing inbox previews

Testing helps ensure that campaigns behave consistently across inbox environments.

LINK Mobility provides solutions for different email use cases.

By combining audience insight with structured email delivery, businesses can align communication with how recipients actually use email clients.

Did you find the article and topic interesting?

If you would like to explore the subject further, discuss ideas, or understand how it could apply to your business, we are here to continue the conversation.

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