JSON Viewer Online - Interactive JSON Tree View
Updated
Navigate deeply nested API responses using an interactive tree view. Discover schema structure and find data without drowning in raw text—100% client-side, your API data never leaves your browser.
Key Features
- ✅ Interactive tree view
- ✅ Collapsible nodes
- ✅ Type-tagged values (string/number/boolean/null)
- ✅ Deep nesting support
- ✅ Client-side only
How to Use
- Accept JSON input via textarea or file upload
- Parse JSON and recursively build tree structure
- Create collapsible nodes for objects and arrays, distinguishing empty [] / {} from null
- Display key-value pairs with type information (string, number, etc)
- Show node depth and count for arrays
- All logic is client-side; no data leaves the browser
- Auto-expand all nodes on load so the full structure is visible immediately
Expert FAQ
- How do I find a specific field in a deeply nested response?
Every node is expanded when the data loads, so the whole structure is visible at once. Use your browser find (Ctrl+F or Cmd+F) to jump to a key or value, and collapse the branches you do not need. - Does it distinguish between an empty array, an empty object, and null?
Yes — each renders with a distinct visual marker ([] , {}, and null respectively) rather than collapsing to the same "empty" representation, since those are three different values with different meanings to a consumer reading the response, and conflating them in the tree view would hide a real distinction in the data. - What about large API responses with thousands of keys — will the tab freeze?
The viewer expands every node on load so the full structure is visible immediately. That is quick for typical API responses; for multi-megabyte payloads, collapse the top-level branches you are not inspecting, or pretty-print the file with the JSON Formatter and read it as text. - How large a file can it handle?
Everything runs in your browser tab, so the practical limit is your device's memory. Typical API responses of a few MB open instantly. Files in the tens of MB work but take longer to build the tree; for anything bigger, a streaming command-line tool such as jq is the better fit.
Technical Details
Unfamiliar, deeply nested API responses (GraphQL, REST, third-party webhook payloads) are effectively unreadable as raw text — you end up manually counting braces to figure out which closing brace matches which opening one. This viewer parses the JSON once and renders it as an interactive, collapsible tree, with each value tagged by its actual JSON type (string, number, boolean, null, array, object) via a visible type indicator, since a bare "42" and a bare "\"42\"" look identical in raw text but are meaningfully different values. Empty collections are rendered distinctly from null: an empty array, an empty object, and a null value are three different pieces of information about a field (respectively: "a list that has zero items," "an object with no properties," and "explicitly no value") and collapsing them into one generic "empty" indicator would erase that distinction — which matters when you're trying to understand why a downstream consumer treats an empty-but-present array differently from a missing or null field. The tree currently auto-expands every branch when data loads rather than rendering lazily, so a response with thousands of keys builds its entire DOM tree upfront rather than only the parts you've opened. If the input JSON is minified, it's parsed and tree-rendered directly — no separate formatting step needed first, though the JSON Formatter is useful if you want a flat, copyable text version rather than an interactive tree.