Check Excel files in the browser, before you take them.
82excel is a free (MIT) library that reads xlsx, xls and csv files and checks them against header rules. Drop your own file into the checker below: it reports passwords, corruption, format and column names right away.
Free online Excel checker
Files are not uploaded. They are checked only inside this browser.
Alternative: https://82excel.com/cdn/v0.1.0/82excel.min.js · version 0.1.0 · install from npm
LightOne CDN file (the Excel82 global, <excel-82> and English and Korean messages) is 28.8 KB gzipped. The only runtime dependency is fflate.
Files and their contents stay putFiles are read in the browser only. A file goes to a server only when you turn on the upload attribute, and then only to your own server.
Password and corruption detectionPassword-protected xlsx/xls, Excel's built-in password, corrupted and mislabeled files come back as error codes, never as exceptions.
EUC-KR and templatesUTF-8, UTF-16 and EUC-KR CSV are detected; Korean headers are compared NFC-normalized. Offer a headers-only template (csv or xlsx) for download.
Two ways to use it
1. Functions only (script)
Call Excel82.check / inspect / readRows yourself. No UI, just the result object; the same functions run in Node.