About
About CSV Lark
Small, fast CSV tools for the moments when opening a spreadsheet app is too much: look at a file, fix it, convert it, move on.
What it is
CSV Lark is a collection of free tools for comma-, semicolon-, tab- and pipe-separated files: a viewer and editor for large files, a cleaner, a duplicate remover, converters to SQL, Markdown and Excel and back, plus merge, split, diff and a test data generator. There is no account, no sign-up and nothing to pay.
How it works
Every tool runs as JavaScript in your browser. When you open a file, the browser reads it from your disk into memory; parsing, cleaning and converting happen on your device, and downloads are created locally too. Your data is never uploaded, which is also why the tools keep working if your connection drops after a page has loaded.
The heavy lifting is done by open-source libraries: PapaParse for CSV parsing, fflate for ZIP files, and read-excel-file and write-excel-file for .xlsx workbooks. Icons come from Lucide.
Working with JSON?
Our sister site JSONMender converts JSON to CSV and CSV to JSON, and repairs broken JSON along the way.
Why a lark?
Larks are small, cheerful and up early. That is the idea: a light tool you can reach for first thing, before you need anything heavier.