CSV Inspector

Paste, drag in, or upload a CSV file. Delimiter (comma/semicolon/tab/pipe) and header row are auto-detected — both can be overridden if the guess is wrong. Parsing runs in a background Web Worker so a large file doesn't freeze the page while it's being read. Pasting a JSON array instead converts it to CSV. Runs entirely in your browser; nothing you paste or upload is sent anywhere.

Notes

Delimiter and header detection are heuristics — both are shown in the status line and can be overridden with the dropdowns above if the guess is wrong, then re-parse. "Malformed" rows are ones whose field count doesn't match the most common field count in the file (a sign of an unescaped delimiter or a truncated row); "duplicate" rows are exact matches of another row's full contents. Renaming columns, hiding columns, searching, and sorting all apply to the exported CSV/JSON, not just the on-screen table. Only up to 100,000 rows are held in memory for the interactive table/export at once, to keep the page responsive on very large files — this is a memory safeguard, separate from (and in addition to) the Web Worker parsing itself.