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: October 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 & Performance 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. Third-Party Advertising & Google AdSense
To support the free availability of our in-browser converters and financial tools without charging subscription fees, ConvertSheet displays advertisements served by third-party advertising partners, including Google AdSense.
- Third-Party Vendor Cookies: Third-party vendors, including Google, use cookies, web beacons, and similar tracking technologies to serve ads based on a user's prior visits to ConvertSheet or other websites on the internet.
- Personalized Advertising: Google's use of advertising cookies enables it and its partners to serve ads to users based on their visits to our website and/or other sites across the internet.
- Opting Out of Personalized Ads: Users may opt out of personalized advertising at any time by visiting Google Ads Settings. Alternatively, users can opt out of a third-party vendor's use of cookies for personalized advertising by visiting the Network Advertising Initiative / Digital Advertising Alliance consumer choice portal at www.aboutads.info.
- Non-Personalized Ads: If personalized advertising is disabled, ads displayed on ConvertSheet will be contextual (based on the general topic of the tool or page being viewed) rather than tailored to your past browsing history.
Important Privacy Distinction: While third-party advertising partners manage ad delivery cookies, your actual spreadsheet contents, JSON files, loan figures, and confidential file data are processed exclusively inside your device's client-side browser memory and are never accessible to or shared with advertisers or third-party networks.
5. 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.
6. Contact & Inquiries
If you have questions or security inquiries regarding ConvertSheet's architectural design or privacy practices, please contact us at privacy@convertsheet.com.