Text Template (Mail Merge)

A mail merge that never leaves the page. Write a template with {{key}} placeholders, paste the data as CSV with a header row or as a JSON array of objects, and get one rendered copy per row, separated by a divider you choose. Placeholders that find no matching column are flagged rather than silently left blank, which catches the typo in {{adress}} before you send forty of them.

The CSV reader implements the quoting rules properly: a field wrapped in double quotes may contain commas, and a doubled quote inside it means one literal quote character. That covers the cases that break naive splitting on commas — an address with a comma in it, a company name like Smith, Jones & Co, a note containing a quoted phrase. A quoted field may also contain line breaks, so the multi-line address or note that a spreadsheet export writes stays in one cell instead of splitting its row in two, and a blank line between rows is skipped rather than rendered as an empty copy.

The other difference between the two inputs is typing. CSV gives you strings and only strings, so a numeric column arrives as text and renders exactly as it was written, leading zeros and all. JSON preserves whatever was in the source — numbers render without their formatting, booleans render as true and false, and a null renders as an empty string or the word depending on how it was stored. If a column must appear a particular way, format it before it gets here rather than hoping the renderer will.

The output is plain text, and it is not escaped for any destination. That is the right default for emails, SMS and certificates, and the thing to watch if you paste the result into HTML: a name containing & or < will be taken as markup. Nothing is uploaded, which is the reason to do a merge here rather than in a hosted tool — a customer list, a payroll run or a set of exam results never leaves your machine, and closing the tab is the whole of the cleanup.