Variable content
Personalized fields merged into an email body from a database or CSV at send time.
Variable content (also called merge tags, personalization tokens, or dynamic fields) refers to per-recipient values inserted into an email at send time — first name, company, last purchase, account state. The mechanics: the email template contains placeholder tokens like {{firstName}} or %FIRSTNAME%, and the ESP substitutes each recipient's value at send.
Effective variable content goes beyond first name. The best personalized emails reference specific recipient context — last product viewed, last support conversation, last campaign clicked. This requires merging email content with CRM or product data, which most ESPs support via Segment, Customer.io, or direct database integration.
The danger of variable content is fallback failure. If {{firstName}} is empty and the email opens with "Hi {{firstName}}," the recipient sees "Hi ," and immediately knows it's a template. Always specify fallbacks (default to "there" or restructure to avoid first-name dependence). Our CSV merge surface defaults missing fields gracefully and previews every row before send so you catch fallback failures before they ship.