OtterJSON — Private JSON Viewer & Formatter

Format, search and explore JSON in a fast tree view. Exact big numbers, dark mode, no tracking. Pro: diff, JSONPath, tables.

JSON you can actually read, without giving up your privacy. OtterJSON turns raw JSON in your browser into a clean tree you can search. The core is free, needs no account, and your JSON never leaves your computer. ✨ FREE • Click the OtterJSON button or press Alt+Shift+J to format the current tab. Auto-format is optional • Tree, Pretty and Raw views, with light, dark or system theme • Item counts, clickable links, and search across keys and values • Copy any path ($.data.items[0].id) or value with one click • Big numbers keep every digit, and duplicate keys are flagged • Clear errors with line and column • Supports JSONP and JSON Lines / NDJSON • Copy, minify or save as a file, plus a paste-or-drop viewer page ⭐ OTTERJSON PRO • Compare JSON with the previous response, pasted JSON or a file • JSONPath queries and regex search • Table view with sort, filter and CSV export • Convert to YAML or CSV, and generate TypeScript, Go or Python types • Decode JWTs (signatures are not verified), Base64, URL-encoded text and timestamps • Auto-repair almost-JSON and see exactly what was fixed • History and snippets (opt-in, stored only on your device) • 7 extra themes and custom keyboard shortcuts Pro is a one-time $9.99 upgrade. No subscription. 🔒 PRIVATE BY DESIGN • No ads, no analytics, no tracking, no account, no remote code • Your JSON is never sent anywhere, including with Pro • Payments are handled by ExtensionPay (Stripe). The only network connection is the Pro license check with extensionpay.com