TreeJSON — JSON Viewer, Tree View, YAML & XML Formatter

Pretty-print JSON, YAML, XML in your browser. Tree view, search, JSONPath copy, export. Open source, privacy-first, MV3-native.

TreeJSON pretty-prints JSON, YAML, and XML responses in your browser — instantly, locally, and with zero telemetry. Built from scratch on Manifest V3 after the most popular JSON formatter Chrome extension (2M+ users) went closed-source and started injecting third-party scripts in early 2026. WHAT IT DOES TreeJSON detects JSON, YAML, and XML responses by content-type and file extension, then renders a clean collapsible tree view with syntax highlighting, item counts, and indent guides. No setup, no account, no servers. KEY FEATURES • Auto-format JSON, JSON-LD, JSON:API, HAL+JSON, NDJSON, YAML, and XML • Collapsible tree with item counts and indent guides • Full-text search across keys and values with substring highlighting • Right-click any node → copy JSONPath, raw value, or full subtree • Click-to-copy on any primitive value • JSON validator with line-numbered parse errors • Export JSON → CSV (array of objects), TypeScript types, or JSON Schema (Draft-07) • Light / dark / auto theme that follows your OS • Per-tab disable, per-origin disable, regex URL exclude patterns • Keyboard shortcuts (Alt+Shift+J toggle, ⌘/Ctrl+F search) • Works on local files (file://) when you enable file access • Raw / parsed toggle to switch back to source text any time • 100% offline after install — no network requests of its own WHO IT IS FOR Web developers debugging REST and GraphQL responses, backend engineers inspecting payloads, QA engineers verifying response shapes, DevOps reading config files, anyone who lands on a raw JSON URL and wishes it were readable. HOW IT WORKS Open a JSON, YAML, or XML URL → TreeJSON checks the content-type → renders a structured tree → search, copy, export. Zero configuration, ever. WHY TREEJSON • Privacy-first. Zero telemetry, zero analytics, zero third-party scripts, zero servers. • Open source. MIT license. The detection code is auditable in the public repository. • MV3-native. Built for Chrome's current extension platform. Will not be disabled by future Chrome updates that retire Manifest V2. • Minimal permissions. Only "storage" for preferences and "activeTab" for the current page. The "<all_urls>" host permission is used exclusively to read the response content-type. • Multi-format. JSON, YAML, XML — one tool, three viewers, one consistent UI. PERMISSIONS EXPLAINER Why does TreeJSON request access to all websites? JSON, YAML, and XML APIs are hosted on every domain on the web. To auto-format a JSON response from any domain, Chrome requires us to declare access to that domain. TreeJSON only inspects the document's content-type. If the response is not JSON, YAML, or XML, the content script exits immediately. No browsing history is read. No URL leaves the browser. Nothing is sent anywhere. COMING FROM ANOTHER JSON VIEWER? Looking for an open-source JSON viewer with no telemetry, no third-party scripts, and a current MV3 codebase? TreeJSON is the privacy-first, multi-format option. Switch in seconds. FAQ Q: Will TreeJSON inject popups or banners on shopping or checkout pages? A: No. TreeJSON never runs on non-JSON pages. The content script exits before reading the page if the content-type is not JSON, YAML, or XML. Q: Does TreeJSON track my browsing? A: No. TreeJSON has zero outbound network requests. It does not load remote scripts, fonts, or analytics SDKs. Q: Why does it ask for "<all_urls>"? A: JSON APIs are hosted on every domain. TreeJSON checks the response content-type and exits if it is not relevant. No URL is logged or transmitted. Q: Can I edit JSON? A: TreeJSON is read-only in v1. Use a dedicated JSON editor for writes. Q: Does it work offline? A: Yes. After install, TreeJSON runs entirely locally. There is no server component. Q: Is the source code public? A: Yes. MIT-licensed on GitHub. Audit the detection logic, the parser glue, and the rendering code before you install. Q: How is this different from Chrome DevTools? A: DevTools shows JSON in the Network tab and requires you to open it for every request. TreeJSON auto-formats every JSON URL you open in a regular tab — faster for everyday API inspection, walkthroughs, and screen sharing.