Data Helper Toolkit

JSON, CSV, Excel and PDF tools: view, edit, format, compare, convert, escape and search — all offline in your browser.

Data Helper Toolkit puts 19 everyday data tools on one page, and runs all of them entirely inside your browser. Nothing is uploaded, and there is no account to create. JSON • Viewer — browse large documents as a collapsible tree, with an inspector for the selected node • Big JSON Editor — syntax highlighting, folding and validation • Formatter & Validator — pretty print or minify, with the exact position of a syntax error • Compare — see precisely what changed between two documents • Stringify and Parse — escape JSON or text into a string literal, and unescape it again Convert • JSON ⇄ Excel, JSON ⇄ CSV, CSV ⇄ Excel • Excel → CSV • JSON, CSV and Excel → PDF • PDF → JSON, PDF → CSV Viewers and search • Text and CSV viewer for large files, as raw text or as a table • Search and replace across large JSON and text files, with regular expressions Built for big files Parsing, diffing and converting all happen on background threads, and only the visible rows are rendered — so a file with hundreds of thousands of rows scrolls without freezing the page. Private by design The extension requests no permissions at all. It cannot read the pages you visit, and it never sends your data anywhere, because it has no network access. Your files never leave your computer.