Why I Built an In-Browser Excel Editor and Chart Studio with Zero Server Uploads

San — Sat, 14 Nov 2026 19:34:07 +0000

Hi HN,

I built SheetCombine (https://sheetcombine.com) because I was constantly frustrated by three things when dealing with spreadsheets:

The Cloud Privacy Problem: Almost every online CSV/Excel converter or merge tool forces you to upload your confidential spreadsheets (customer emails, financial records, pricing) to a random remote server.
The Microsoft / Power BI Wall: Power BI Desktop is notoriously Windows-only. If you're on a Mac, Linux, or Chromebook and just want to turn a CSV or Excel sheet into a clean bar/line chart and get instant KPI metrics, you have to jump through hoops or pay for cloud subscriptions.
The VLOOKUP / XLOOKUP Headache: Non-technical teammates constantly struggle with #N/A errors, trailing whitespace mismatches, or syntax errors when trying to merge two sheets together.

How it works technically:

100% Client-Side: Everything runs locally inside browser memory using WebAssembly and client-side JavaScript.
Zero Telemetry on Data: Your files, rows, and cells never leave your device. You can disconnect your Wi-Fi or turn on Airplane mode and the entire grid, formula recalculation, and chart visualizer still function.
PWA & Offline: It installs as an offline Progressive Web App on Mac, Linux, Windows, or ChromeOS.
Features:
- Full spreadsheet grid with 40+ formulas (=SUM, =IF, =AVERAGE, =VLOOKUP)
- 1-click Column Combiner & Delimiter Splitter
- 2-Sheet Left Join / Merge without writing formulas
- Power BI-style Chart Studio (Bar, Line, Area, Doughnut) with 4 auto-calculated KPI cards (Sum, Mean, Count, Peak) and 1-click PNG image export
- Clean export to styled XLSX, CSV, TSV, Markdown, JSON, and SQL INSERT scripts

It's completely free, requires zero account or sign-up, and has zero paywalls.

I’d love your brutal feedback, bug reports with weird CSV encodings, and feature suggestions!

DEV Community: San