GLOSSARY
Mail merge
By Justin Winter · Updated August 28, 2026
The short answer
Generating one personalised letter per row of a data file by filling named fields in a single template.
A mail merge pairs a template containing placeholders with a spreadsheet or database of recipients, producing one document per row. It is how a hundred individually addressed letters get made without writing a hundred letters.
The mailing half is separate from the merging half: something still has to print, stuff, stamp, and hand each piece to USPS.
See also
- Variable data printing — Digital printing where content changes from piece to piece — names, amounts, images — without stopping the press.
- Print-and-mail API — An API that accepts a document and a recipient address and returns a mailed physical letter — printing, envelope, postage, and USPS handoff included.
- USPS Marketing Mail — The bulk advertising class, formerly Standard Mail: cheaper per piece, but it requires a permit, a minimum volume, presorting, and it travels slower.
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