CSV Editor & Converter

A spreadsheet opens your export and starts making decisions about it. A code that begins with a zero loses it. A long product number turns into scientific notation. A date column becomes numbers. Names with accents arrive as garbage.

This opens the same file and leaves your values alone.

WHAT IT WORKS OUT FOR YOU
It reads the byte-order mark, or failing that tries UTF-8, then Windows-1252, then Latin-1, then ASCII — and tells you which it picked. It reads the first hundred lines to work out whether your delimiter is a comma, a semicolon, a tab or a pipe, and tells you that too. Both show an "auto" chip, and both have a picker if it guessed wrong, which flips the chip to "manual" so you always know which you are looking at.

WHAT IT WILL NOT DO TO YOUR DATA
Every value is moved as text. No autocorrect. No date reformatting. No dropped leading zeros. No scientific notation. That holds for the table you see and for CSV and TSV export. Column types are worked out so it can check the file, and nothing is rewritten unless you ask for it — Fix Warning on a cell you have selected, a column transform for whitespace or case, or a Replace All that you run yourself.

IT TELLS YOU WHAT IS WRONG
Every row is checked, not a sample. You get the row and column of anything whose column count is off, or whose value does not match the column's type — "Expected integer, found 'N/A'". Integer, decimal and boolean only; it does not check dates, emails or URLs.

EDITING
Cells and headers in place, add and delete rows and columns, duplicate rows, Tab and Return to move, find and Replace All, and fifty steps of undo.

GETTING IT OUT AGAIN
CSV, TSV or JSON. For CSV and TSV, choose the export encoding independently of the one it read, so a file that arrived as Windows-1252 goes out as UTF-8, and pick the separator for CSV. JSON is always written as UTF-8, and can emit real integer, decimal and boolean types instead of quoting everything — worth knowing that a code like an ID beginning with a zero is a number to JSON, so leave typed values off if you need those kept exactly as written.

IT WORKS WITH THE NETWORK OFF
It ships with no network entitlement at all. If you handle data you are not allowed to upload, the free online converter is not a worse option — it is one you cannot use. And this is the part you can check for yourself rather than take on trust: turn off Wi-Fi and everything still works.

ABOUT THE FREE SPREADSHEET ON YOUR MAC
It is free, it is already installed, and it is a far better spreadsheet than this: formulas, charts, multiple sheets, printing. This app has none of those and no Excel support of any kind. If your file is fine and you just want to work with it, use the free one and keep your money. This is for when the file is not fine.

WHAT IT DOES NOT DO
No Excel. It cannot open or save XLSX, and there is no JSON import.

It reads your file with the right encoding in the first place. It cannot repair text that was already turned to garbage before it reached you — if the sender saved the damage into the file, the characters are gone.

One file at a time — no batch conversion.

No promise about very large files. The whole file is read into memory, so a very large export may not be practical, and there is no row count at which it is guaranteed to work.

Search and sort change what you see, not what you export — an export always writes every row in the original order. Find and replace has no regular expressions. There is no de-duplicate and no column splitting.

Save writes back over the file you opened — use Save As or Export if you want the original left alone. And two things do change on the way out, so they are worth knowing before you overwrite anything: a byte-order mark is dropped and never written back, and Windows or classic-Mac line endings are converted to Unix ones. If you need a file with a BOM, export a copy and add it elsewhere.

One-time purchase. No account, no subscription. Requires macOS 14 or later.