Privacy Policy
ConvertSheet is built on a fundamental principle: your data belongs to you. We believe the best privacy guarantee is not a promise, but technical impossibility.
Last updated: September 2026
100% In-Browser
All spreadsheet conversions, JSON parsers, PDF splits, and financial math run locally in your browser sandbox using WebAssembly and Web Workers.
Zero Server Uploads
Your files never leave your computer or travel over our servers. There is no remote database, temporary file storage, or file cache.
No Data Harvesting
We do not sell, inspect, log, or mine your confidential financial numbers, employee rosters, or proprietary customer files.
1. How Client-Side Processing Works
Traditional file converter websites require you to upload your sensitive CSV, Excel, or PDF documents to a remote cloud server. Once on their server, your files are processed by third-party scripts, stored in temporary buckets, and often retained for days.
ConvertSheet operates differently. When you drag and drop a file into ConvertSheet:
- Your browser reads the file locally into device RAM using the standard HTML5 File and FileReader API.
- Compiled WebAssembly binaries (such as DuckDB-Wasm and Apache Arrow) execute SQL queries and transformations entirely on your machine.
- Output files (e.g. `.xlsx`, `.csv`, `.parquet`, `.pdf`) are compiled locally and downloaded directly to your hard drive via Blob URLs.
2. Zero Server Data Retention
Because files are never transmitted across the network to ConvertSheet servers, we cannot retain, archive, inspect, or accidentally leak your documents. Even if our web servers were compromised, an attacker would find zero customer files, database records, or spreadsheet dumps.
When you close the browser tab or refresh the page, all loaded memory and temporary Blob representations in your browser are automatically purged by your operating system.
3. Analytics & Cookies
ConvertSheet uses minimal, privacy-friendly analytics to track high-level traffic metrics (such as page views, visitor country, and device type). We do not record user session inputs, file names, column headers, cell values, or personal identifiers.
4. Local Storage & Preferences
We store non-sensitive UI preferences (such as your chosen light or dark theme) in your browser's local storage (`localStorage`). This data never leaves your browser and can be cleared at any time in your browser settings.
5. Contact & Inquiries
If you have questions or security inquiries regarding ConvertSheet's architectural design or privacy practices, please contact us at [email protected].