CSV Diff & Converter
Compare two CSV/TSV/Excel files and convert between CSV, JSON, and SQL — all in your browser.
Why Use DiffMergy’s CSV & Excel Diff & Converter?
DiffMergy’s CSV & Excel Diff tool lets you compare spreadsheet data cell by cell, so you can instantly spot added, removed, and changed rows and columns between two CSV or TSV files. It is purpose-built for data analysts, QA engineers, and developers who need to verify exports, migrations, and report changes without opening a heavy desktop app.
Beyond diffing, the built-in converter transforms CSV into JSON, JSON into CSV, and CSV into SQL INSERT statements — perfect for seeding databases, feeding APIs, or migrating data. Everything runs locally in your browser, so your sensitive business data never leaves your machine.
100% Private — No Server Upload
All processing happens entirely in your browser using modern browser APIs. Your sensitive source code, credentials, and files never leave your device — no servers, no databases, no tracking, no sign-up required.
Fast & Reliable
Built with vanilla TypeScript and a lightweight custom engine, DiffMergy delivers sub-millisecond processing with zero network latency. The entire toolkit works on any modern browser across all operating systems, with no installation or setup needed.
Frequently Asked Questions
How do I compare two CSV files?
Paste or upload your original CSV in the left editor and the modified CSV in the right editor, then click Compare. DiffMergy aligns rows and highlights added, removed, and changed cells so you can review data differences instantly.
Does it support tab-separated or semicolon-delimited files?
Yes. Use the Delimiter selector to choose Comma, Tab, Semicolon, Pipe, or Auto-detect. Auto-detect reads the first line to pick the most likely separator.
Can I convert CSV to JSON or SQL?
Yes. Open the Convert tab, paste your data, and choose CSV to JSON, JSON to CSV, or CSV to SQL. The output is generated entirely in your browser and can be copied to your clipboard.
Is my spreadsheet data private?
Absolutely. All parsing, diffing, and conversion run locally in your browser. Your CSV, JSON, and SQL data never leave your device and are never uploaded to any server.