{"slug": "show-hn-cleanmysheet-privacy-first-csv-excel-cleaner-that-runs-in-the-browser", "title": "Show HN: CleanMySheet – Privacy-first CSV/Excel cleaner that runs in the browser", "summary": "CleanMySheet, a new privacy-first CSV/Excel cleaner, runs entirely in the browser with Strict mode enabled by default, ensuring files and column samples never leave the device. The tool offers scan, review, and apply workflows with reusable recipes, and a free export of 500 rows, with a Pro tier at $9/month launching soon.", "body_md": "Everything runs in your browser. Strict mode (on by default) never sends column samples.\n\nScan → Review → Apply\n\nSee exactly what will change before anything is modified. Undo any step.\n\nReusable recipes\n\nDownload a recipe JSON. Drop it with next month’s file to replay the same steps.\n\nWhat is spreadsheet cleaning?\n\nSpreadsheet cleaning is turning a messy CSV or Excel export into a consistent table: one date format, blank cells instead of N/A, no accidental duplicate rows, parsed numbers, and split name or address fields. CleanMySheet does that in the browser with named, reversible steps — not by pasting the file into a chatbot.\n\nHow to clean a CSV or Excel file\n\nDrop a .csv, .xlsx, or .xls file. Nothing is uploaded in Strict mode.\n\nRead the scan for duplicates, dates, phones, empties, and names.\n\nApply Recommended or search presets (CRM, finance, survey).\n\nPreview Original, Cleaned, and Diff. Undo any step.\n\nExport CSV (free: 500 rows), a recipe, and a quality report.\n\nNo. Files stay in your browser. If you join the Pro waitlist we store only the email you give us so we can notify you when sign-in and checkout are live.\n\nIs it safe to upload customer data to an online CSV cleaner?\n\nOnly if the tool processes in the browser. CleanMySheet’s Strict mode (default on) does not send column samples or rows to a server.\n\nWhat is the best free way to clean a CSV file online?\n\nUse a client-side cleaner like CleanMySheet: drop the CSV, apply trim/dates/dedup presets, preview the diff, and export. Strict mode keeps the file on your device. Free export is 500 rows.\n\nCan I clean Excel XLSX in a browser?\n\nYes. CleanMySheet parses XLSX with SheetJS, including multi-sheet workbooks and serial dates, without uploading the file in Strict mode.\n\nHow do I remove duplicate rows in Excel without losing similar contacts?\n\nRun exact dedup for identical rows, then fuzzy matching for near-duplicates. CleanMySheet flags John Smith vs Jon Smith for review instead of auto-deleting.\n\nHow do I fix mixed date formats in a spreadsheet?\n\nParse each cell from the column’s own samples (day-first vs month-first), plus Excel serials, then write one output format. Default is YYYY-MM-DD. Ambiguous values like 03/04/2022 are left alone unless the rest of the column makes the order obvious.\n\nHow many rows can I export for free?\n\nYou can preview the whole file. Free CSV export is capped at 500 rows. Recipe JSON and the quality report are not row-capped.\n\nCan I reuse the same cleaning steps next month?\n\nDownload a .cleanmysheet.json recipe. Drop it with the new CSV to append the same operations. Matching headers also trigger a local recall prompt.\n\nReady to clean your spreadsheet?\n\nFree export 500 rows. No account needed.\n\nDrop CSV or Excel here\n\nTap to choose a file. Parsing stays on this device.\n\nParsing stays on this device. Optional: drop a .cleanmysheet.json recipe with it.\n\nFree export is 500 rows. Pro ($9/mo) launching soon.", "url": "https://wpnews.pro/news/show-hn-cleanmysheet-privacy-first-csv-excel-cleaner-that-runs-in-the-browser", "canonical_source": "https://cleanmysheet.in", "published_at": "2026-08-28 15:33:14+00:00", "updated_at": "2026-08-28 15:48:26.464043+00:00", "lang": "en", "topics": ["ai-tools"], "entities": ["CleanMySheet", "SheetJS"], "alternates": {"html": "https://wpnews.pro/news/show-hn-cleanmysheet-privacy-first-csv-excel-cleaner-that-runs-in-the-browser", "markdown": "https://wpnews.pro/news/show-hn-cleanmysheet-privacy-first-csv-excel-cleaner-that-runs-in-the-browser.md", "text": "https://wpnews.pro/news/show-hn-cleanmysheet-privacy-first-csv-excel-cleaner-that-runs-in-the-browser.txt", "jsonld": "https://wpnews.pro/news/show-hn-cleanmysheet-privacy-first-csv-excel-cleaner-that-runs-in-the-browser.jsonld"}}