How can I open a CSV file without scrambled columns or corrupted accents?
Drag and drop your file into CSViewer. The parser automatically detects commas, semicolons, tabs, and pipes, as well as UTF-8, Latin1, and Windows encodings.
Files
CSViewer
FreeLocal processingv1.0.0
Open, view, and edit CSV and XLSX spreadsheet files online. Filter, standardize dates, phones and numbers, remove duplicates, and split into ZIP archives.
About this app
Open and edit CSV and XLSX spreadsheet files instantly in your browser with high performance and zero data uploads.
Drag and drop large files without freezing: CSViewer handles multi-line headers, semicolon, comma, and tab delimiters, and auto-detects UTF-8 and special character encodings.
Navigate seamlessly using keyboard shortcuts, arrow keys, and Excel-style cell selection. Format columns with one click: convert dates, clean phone numbers, format currency (USD, EUR, GBP, BRL and custom symbols), and standardize CPF/CNPJ.
Perform bulk edits across multiple columns: change case, add or strip prefixes and suffixes, and apply conditional modifications based on numeric or date rules.
Filter rows by keyword or column criteria and export directly to CSV, TSV, or XLSX. Split massive spreadsheets by row count into clean ZIP packages, or save lists locally in your browser for future work.
100% client-side execution. Your spreadsheets, customer lists, and financial figures remain private and protected on your machine.
Features
Opening spreadsheets with two-line headers (Wix and ERP exports)
In Options, toggle Two-line header. CSViewer will use the second row for clean column titles while keeping the top labels intact.
What to do when the first row contains data instead of headers?
Toggle First row is not header in Options. CSViewer will automatically generate generic column letters (A, B, C...) so no data row is missed.
Remove duplicates, duplicate columns, or extract first names
Click the 3 dots on any column header. Choose Remove duplicates to clean up repeated entries, Duplicate column to make a backup, or Keep first name.
Standardize dates, phone numbers, emails, currency, and create WhatsApp links
Click Format in the column menu to automatically standardize dates, telephone formats (national or international), currency with custom prefixes, and clickable WhatsApp chat links.
Bulk edit cells with numeric, date, or text conditions
Select one or more columns and click Bulk edit. Add prefixes, suffixes, change case, or apply changes conditionally based on greater than, less than, or matching values.
Filter rows by keyword and export filtered results
Click the Filter button in the top bar to instantly search across all cells. Active filters show a clear indicator, and exports will contain only matching rows.
How can I split a large spreadsheet into multiple smaller files?
Open Export and choose Split into multiple files. Enter the number of rows per file, and CSViewer will package all chunks with headers into a single ZIP archive.
Store saved lists locally in your browser to resume later
Click Save to store spreadsheets inside your browser's local database. Open Saved lists anytime to search with keyword highlighting, reload, or export in bulk.
Frequently asked questions
Are my spreadsheet data processed locally or sent over the Internet?
Everything is processed 100% locally on your computer or mobile device. No spreadsheet cells or rows are transmitted across the web.
Is it safe to open customer lists, phone numbers, and financial sheets in CSViewer?
Yes. Because CSViewer operates entirely in-browser without back-end storage, sensitive data remain strictly in your local device memory.
Can I navigate and edit cells on desktop and mobile like in Excel?
Yes. Use arrow keys, Enter, and Tab to move between cells, double-click or press Enter to edit, drag selection handles, and use standard copy-paste shortcuts.
In which formats can I export my spreadsheet after adjustments?
You can export directly to CSV (comma, semicolon, or tab), plain text TXT, or Excel XLSX files, either as a single file or split into a ZIP archive.
Where are saved lists stored inside the application?
Saved lists are stored safely in your browser's private IndexedDB storage. They do not expire and remain accessible only to you on this device.
Questions
No published answers yet.
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