preheader

A preheader, also known as preview text, is a short summary or snippet of an email’s content that appears in many email clients alongside or beneath the subject line in the inbox view. It can be sourced from a dedicated preheader field provided by the email service or from the first lines of the email body. The preheader is designed to give recipients additional context and encourage them to open the message.

The primary purpose of a preheader is to enhance open rates by providing a concise preview of the email’s value or content. It complements the subject line and can help differentiate the email from others in the inbox, especially when many messages share similar subjects.

Construction and implementation vary. Some email marketing platforms offer a specific preheader text field that you populate, which the client will display as the preview. In HTML email markup, developers may place a short string at the top of the body and, if necessary, use techniques to keep it visually hidden in the message body while still being read by email clients. The key is that the preheader should not duplicate the subject line and should add information or value.

Best practices include keeping the preheader concise (often 40 to 130 characters, depending on the client), ensuring it adds new information, aligning it with the subject line, and avoiding vague or misleading copy. It should be tested across major email clients and devices to confirm how it is displayed.

Examples might be:

- Subject: New arrivals today

Preheader: Fresh styles just landed—free returns for 30 days.

- Subject: Your weekly deal roundup

Preheader: Save up to 50% on selected items before Sunday.

Accessibility and analytics considerations apply: use clear language, and measure performance to optimize over time.