JSON Formatter & Viewer

Offline JSON formatter & viewer: beautify, tree view, diff, JSONPath & smart repair. 100% local — no data leaves your browser.

JSON Formatter Pro is an instant, 100% offline tool built for developers to format, view, and debug JSON—without sending a single byte to an external server. CORE FEATURES - Beautify and Explore: Format JSON with syntax highlighting. Toggle between raw text and an interactive tree view. - 100% Private: All processing runs locally in your browser via Web Workers. Zero analytics, tracking, or telemetry. PRO TOOLS - Smart Auto-Repair: Safely fix common formatting errors (trailing commas, single quotes, unquoted keys, comments) using a custom parser—no dangerous eval(). - Side-by-Side Diff: Compare two JSON structures with synchronized scrolling and automatic change detection. - JSONPath Query Engine: Search and filter complex data using wildcards, array slices, and recursive descent. PERMISSIONS This extension uses minimal permissions: storage to save your settings and drafts, and activeTab to format JSON on your current page.