Mail Merge from CSV

About mail merge

This tool does a classic mail merge: it fills a text or markdown template once for every row of a CSV, then joins the results. Each {{Column}} placeholder in the template is replaced by that row's value for the matching CSV header column, so one small template plus a spreadsheet of data becomes a batch of personalized letters, emails, labels, reminders, or messages.

Everything runs locally in your browser. Your template and data are never uploaded to a server, and it works offline.

How it works

1. Template — write your text and drop {{name}} style placeholders where the per-row values should go. The name inside the braces must match a column header in your CSV.
2. CSV data — paste rows where the first line is the header (the column names) and each following line is one record.
3. Pick the placeholder style, the CSV delimiter, and a separator to put between the generated documents, then run.

Worked example

Template:

Hi {{name}},

Your invoice for ${{amount}} is due on {{due}}.

Thanks!

CSV:

name,amount,due
Alice,120,2026-08-01
Bob,90,2026-08-05

Output (with the default --- divider between rows):

Hi Alice,

Your invoice for $120 is due on 2026-08-01.

Thanks!

---

Hi Bob,

Your invoice for $90 is due on 2026-08-05.

Thanks!

Options

• Placeholder style — {{column}} (double curly, default), {column} (single curly), or <<column>> (double angle). Pick whichever doesn't clash with literal braces in your template.
• CSV delimiter — comma (default), semicolon (common in European exports), or tab (TSV).
• If a placeholder column is missing — replace with nothing (the usual mail-merge behavior), keep the {{placeholder}} text (handy for catching a typo in a field name), or show an error.
• Case-insensitive matching — on by default, so {{First Name}} matches a header called first name.
• Separator between documents — a --- rule (default), a blank line, a single newline, a page break (form feed), or none.

Limits and edge cases

• Up to 1000 data rows per merge (an in-browser memory bound). Split larger lists into batches.
• A placeholder for a column that exists but is empty on a given row always renders as an empty string, regardless of the missing-column setting.
• A row with fewer fields than the header treats the absent trailing cells as empty.
• Quoted CSV fields ("a, b") may contain the delimiter and newlines.
• This is plain named substitution — there are no loops, conditionals, or expressions. For Handlebars/Mustache logic against a single JSON object, use the render-template tool instead.

FAQ