Clean and fix CSV files — no upload

Repair common CSV problems including wrong delimiters, uneven rows, empty lines, whitespace, BOM markers, and duplicate headers.

Clean one messy CSV entirely in your browser without uploading it, up to 100 MB. The cleaner detects the delimiter, removes fully empty rows, trims surrounding whitespace from headers and cells, fills blank headers, makes duplicate header names unique, and normalizes uneven rows to the widest row before writing a cleaned UTF-8 CSV with the delimiter you choose. It handles one file at a time. An unclosed quote in the final row is salvaged and reported; if a row exceeds what the browser can safely process, the run stops with an error instead of silently dropping it. The cap is limited by processing time rather than memory: the cleaner reads the input twice, first to plan the widest row and then to write the output, so a file near the cap can take noticeable time on a slower computer.