Email compatibility testing is the process of testing an email HTML code before executing a campaign. Email compatibility tests are needed because some HTML codes and tags can’t be rendered by some email clients and webmails. Furthemore, rendering capabilitie may differ for a same email client or webmail according to browsers, OS and devices.
Email compatibility tests may have two forms, rendering test and code compatibility analysis. Rendering tests show how an email is rendered or displayed by different email clients (see inbox preview for more details.
HTML code compatibility analysis search for HTML tags which can’t be interpreted by some email clients.
An example of code compatibility test against many email clients and webmails (Image credit Litmus):