Free JSON Formatter

Fast, private JSON viewer. Collapsible tree, search, themes. No ads, no tracking, no network requests. Open source.

Free JSON Formatter turns any raw JSON page into an interactive, collapsible, syntax-highlighted tree - instantly, and entirely inside your own tab. PRIVACY, VERIFIABLE - No ads. No affiliate code. Nothing is injected into any page you visit. - No telemetry, no analytics, no tracking. - Zero network requests - the extension has no server to talk to. - One permission: "storage", used only to remember your own settings. - Open source (MIT). Read every line: github.com/andret2344/free-json-formatter - Under 30 kB packed. No remote code, no bundled SDKs. These are checkable claims, not promises. The end-to-end test suite asserts that formatting a document makes no network request at all, and the privacy policy lists every single key the extension writes to your device. FEATURES - Automatic detection of JSON pages (application/json, .json URLs, or a plain <pre></pre> of valid JSON) - Collapsible tree with lazy rendering - multi-megabyte documents stay responsive - Syntax highlighting for keys, strings, numbers, booleans and null - In-tree search with match count, next/previous, and case-sensitivity toggle - it searches the parsed JSON, so it finds matches inside branches you have not opened yet - Line numbers that stay stable when you fold, exactly like code folding - Copy path - hover any line, copy a console-ready accessor (json.items[0].id) straight into devtools, where the document is already exposed as "json" - Line links - click a line number to get #L21 in the address bar; the link reopens that exact line later - Expand all / Collapse all, cancellable, plus Ctrl/Cmd+click to fold a whole level - Formatted / Raw toggle - the original text is one click away - Copy raw or copy re-indented JSON - Indent guides, highlighted for the level under your pointer - Clickable URLs inside string values - Themes: Auto (follows your OS), Light, Dark - Configurable indentation: 2/4/6/8 spaces, or 1/2 tabs - Line wrapping toggle - Settings for maximum payload size and initial tree depth - the popup never reloads your tab, so nothing on screen is thrown away BUILT FOR BIG DOCUMENTS Large files open at a sensible depth instead of dumping 20,000 lines on you. Branches are rendered only when you open them. Expanding a huge tree runs in batches you can cancel at any time. Works on Chrome, Edge, Brave, and Firefox. Source: github.com/andret2344/free-json-formatter Issues: github.com/andret2344/free-json-formatter/issues