JSON Toolbox

High-performance JSON Toolbox: format, minify, escape and compare locally. No ads, tracking or data collection.

JSON Toolbox puts performance and privacy first. Click the extension icon to format, browse and compare JSON in a dedicated tab. It works fully offline, with no account or extra permissions required. Web Workers, virtual tree and text views, and reused parsing results reduce interface blocking and repeated work with large JSON; performance depends on your device and data structure. Formatter page: - Beautify with 2-space / 4-space / Tab indent - Syntax error messages, with line/column and navigation when the browser provides location details - Collapsible tree view: virtual scrolling, expand-to-level, key/value search with match navigation - One-click copy Minify, escape and unescape pages: - A separate page for each tool, connected by consistent sidebar navigation - Minify JSON and report invalid input, including error locations when available - Escape and unescape JSON string content, with one-click copy Compare page: - Structural diff between two JSONs: added / removed / changed / type-changed by path - Arrays compared by index or matched by a key field (e.g. id) - Optional ignore paths (e.g. timestamp fields) - Full tree with highlighted diffs, or diffs-only mode, with per-diff navigation - Line-level text diff view Privacy: all processing stays in your browser. No data collection or uploads, network requests, remote code, ads or tracking. Input history is not saved, and results are written to the system clipboard only when you copy. Large results use virtual rendering, so native browser Find covers only the visible window. Tree search and full copying remain available. Complete inputs and results stay in memory; large text diffs use block replacement.