How It Works Under the Hood
PapaParse and SheetJS decode multiple local CSV/TSV and XLSX workbooks inside browser RAM, union column headers automatically, deduplicate normalized key columns, and stream clean outputs back as UTF-8 BOM CSV, XLSX, or split ZIP archives.
Step-by-Step Instructions
Drop one or more CSV, TSV, or Excel (.xlsx/.xls) files.
Toggle duplicate removal on Email, Phone, or custom key columns and enable UTF-8 BOM if opening in Excel.
Download the unified clean CSV/XLSX or split massive tables into fixed-size chunks inside a ZIP.
Key Features & Performance
- Multi-File Header Union: Automatically aligns columns even when files have differing header order
- Smart Key Deduplication: Deduplicate millions of cells locally by Email, Phone, or full row
- UTF-8 BOM Excel Fix: Prevents Vietnamese and accented Unicode garbling in desktop Excel
- Chunk Splitter to ZIP: Break oversized exports into clean numbered CSV parts
Local Browser Processing & Privacy
Traditional web converters upload your documents, snippets, or media files to remote servers. CSV / Excel Merger, Splitter & Cleaner runs inside your browser tab:
Your input text and files are processed locally without uploading payloads to a processing server.
Microdeck does not log or store the files or inputs you paste into tool workspaces (normal static hosting/CDN requests still load page assets).
Working outputs stay in your browser tab and are released when you reset the tool or close the tab.
Frequently Asked Questions
Can Excel corrupt UTF-8 CSV files without BOM?
Yes. Microsoft Excel often opens UTF-8 CSV files without a Byte Order Mark as Windows-1252, mangling accented characters. Checking Add UTF-8 BOM fixes this automatically.
Are customer rows ever sent to a backend server?
Never. All parsing, merging, deduplication, and ZIP packaging execute strictly in browser memory.
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