About CSV Splitter Online

CSV Splitter Online is a free, browser-based toolkit for working with CSV, TSV, and Excel files. We built it because the existing online CSV tools had the wrong trade-offs: most require file upload, which is unacceptable for sensitive data (customer lists, financial exports, HR records, healthcare data); many have file-size limits or paywalls beyond 10 MB; most corrupt data silently, stripping leading zeros from ZIP codes or turning "01/02" into a date.

Our approach

Every tool on this site runs entirely in your browser using JavaScript. Your file is read by the browser's built-in File API, processed locally, and the output is downloaded from memory — no server round-trip exists. You can verify this by opening your browser's Network tab while using any tool. There will be zero outgoing requests with your file data.

Why this architecture

It's the only architecture that makes the privacy promise technically enforceable rather than contractual. A site that uploads your file and "promises" not to look at it is one database breach away from a disaster. A site that never sees your file has nothing to breach.

Engineering principles

• Data fidelity first. Leading zeros stay, encoding is detected correctly, nested JSON round-trips cleanly, booleans stay booleans. Excel and most CSV tools fail at this — we treat it as the core product.
• No size limits except your browser's memory. 500 MB files work. 2 GB files work on Chrome/Edge. No artificial caps.
• Fast on the common path. Most files process in under a second. Large files show real progress bars, not fake spinners.
• Accessible. Every tool works with keyboard navigation, screen readers, and both light and dark themes. WCAG 2.1 AA targeted.

How we fund this

Hosting and domain costs are covered by non-intrusive Google AdSense ads. There's no premium tier, no "upgrade to unlock larger files", no account gating. If the ads ever become annoying, tell us — the goal is to keep the tools genuinely free, not to optimize for impressions.

Who uses it

Salespeople preparing customer imports for Salesforce and HubSpot. Marketers cleaning email lists for Mailchimp. Data engineers doing quick CSV operations without firing up Python. Analysts who need to merge monthly exports. Compliance-sensitive teams who cannot upload their data anywhere.

Contact

Questions, bug reports, feature requests: [email protected].