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What is Merge Tag?
A placeholder token in an email template that is replaced with recipient-specific data from a list or CRM at send time.
A merge tag, also called a merge field or variable, is written as a token such as {{first_name}} or %COMPANY% that the sending platform substitutes with the matching column value for each recipient. Merge tags are the mechanism that makes personalization scale across a list. When the underlying data is missing or blank, the tag can render as an empty string and produce broken copy like "Hi ,", which is why fallback values are essential.
Why it matters for cold email
Broken merge tags are an instant tell that an email is an automated blast, tanking reply rates and inviting spam complaints. Cold senders must validate that every recipient has the data each tag needs and configure sensible fallbacks, since a visible {{first_name}} or an empty greeting is worse than no personalization at all.
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