Tag: #file-api
2 articles
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Build an online XLSX viewer in React — files never leave the browser
Most 'XLSX viewer online' tools upload your spreadsheet to a server you don't control. Here is a complete React component that opens .xlsx files entirely in the browser — read-only, with styles, merges, and formulas preserved. No upload, no backend, no account.
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Importing real Excel files in the browser — no upload, no server
Drag an .xlsx file onto a web page, render it in a spreadsheet UI with cell styles, merges, borders, freeze panes, and formulas preserved. No backend, no SheetJS, no progress modals — and it loads a 440k-cell file in 3.7 seconds.