spreadsheet comparison
PlanilhaKit
Desktop MVP that compares CSV and XLSX spreadsheets locally, by one or more key columns, and exports the differences.
MVP in development
The problem
Checking two versions of a spreadsheet by hand is slow and error-prone, and many people cannot upload these files to an online service. I built PlanilhaKit to do the comparison on the user's own computer.
What it does
- Pick two spreadsheets (CSV or XLSX) with the native file dialogs.
- Choose the sheet and header row for XLSX, or the delimiter for CSV, and preview the data.
- Compare by a single key or a composite key, regardless of row and column order.
- See added, removed, and modified records, with previous and new values.
- Export the full result as CSV or XLSX.
The technical decision
The comparison engine is written in Rust and is independent of the interface; Tauri and React sit on top of it through six IPC commands. Matching is exact, with no fuzzy pairing; empty or duplicate keys are rejected with a clear message. Exported reports keep formula-like values inert, so they do not run when opened in Excel.
The result
It is an MVP in development. The engine has 33 automated tests, all passing on Oct 24, 2026, and the Windows CI ran the tests and built an NSIS installer. Limits: no formulas, no mapping of differently named columns, no cancellation, and 32 MiB per file. Installation on a clean Windows machine has not been validated yet.