An email client is the app or service used to read and send email. Learn examples, differences between webmail and apps, and how clients affect rendering.
An email client is a software application or web service used to send, receive, and manage email. Common email clients include Gmail, Outlook, Apple Mail, and Thunderbird, along with many mobile mail apps.
Email clients differ in how they display HTML, handle images, and interpret formatting. This means the same email can look slightly different across clients, which is why email design often relies on conservative HTML structures and extensive testing.
For teams running campaigns, understanding email clients helps with troubleshooting deliverability and rendering issues. It’s also useful for interpreting analytics, since privacy features and image loading behavior vary by client.