JSON Formatter, Validator & Tree Viewer

1. 1Paste your JSON. Paste or type JSON into the Raw input pane. Minified, single-line and pretty-printed JSON all work.
2. 2Read the validation result. The tool validates the input half a second after you stop typing. Valid JSON appears in the tree; invalid JSON shows the error message with its line, column and a pointer to the exact character.
3. 3Explore the formatted tree. Expand and collapse nodes, search with filter or highlight mode, and decode escaped JSON strings into navigable subtrees.
4. 4Copy, download or save. Copy any node as JSON, download the document as a .json file, or save it to your local history to reopen later.

Minified JSON from an API response becomes indented, one value per line, and is shown as a tree you can fold:

{"id":42,"name":"Ada","roles":["admin","dev"],"active":true}

{
  "id": 42,
  "name": "Ada",
  "roles": [
    "admin",
    "dev"
  ],
  "active": true
}

• Instant formatting & beautifying: Paste minified or messy JSON and read it as a clean, indented, color-coded structure.
• Real-time validation with exact error lines: Invalid JSON is flagged immediately with the precise line number and message, so you can fix trailing commas, missing quotes, single quotes, or unquoted keys in seconds.
• Non-blocking parsing: Validation runs in a background Web Worker, so even large API payloads and log dumps don't freeze the page.

These are the messages Chrome, Edge and Node.js report, and the ones this tool shows with the line and column. Firefox and Safari word them differently, but the causes are the same.

• Collapsible tree view: Navigate deeply nested objects and arrays with collapsible nodes and color-coded syntax highlighting.
• Expand all / collapse all: Open the entire structure or fold it back to the top level in one click (or one shortcut).
• Full-width mode: Hide the raw input and give the tree the whole width when you're reading large documents.

API responses frequently embed an entire JSON document as an escaped string inside a field (for example "body": "{\"id\":1}"). Click Decode on that node — or on the whole document — and the tool parses the string in place and expands the result as a real, navigable subtree. Your original raw input is never modified, so you keep the source intact.

• Two search modes: Filter mode shows only matching nodes and their parents; highlight mode keeps the full tree and steps through matches with next/previous.
• Search both panes: Find text in the raw input editor or in the rendered tree; search opens in whichever pane you last used.

• Local saved history: Save JSON snapshots and reopen them later. Entries can be renamed, pinned to the top, and deleted, and they persist in your browser between visits.
• Auto-save & restore: Your most recent input is stored locally and restored the next time you open the tool.
• Copy anything: Copy the whole document, or a single object or array node from the tree as formatted JSON.
• Download as .json: Export the current JSON to a file with one click.
• Dark & light themes: Switch themes manually or follow your system preference; your choice is remembered.

Every action has a keyboard shortcut, and each button's tooltip shows it. Shortcuts use Cmd on macOS and Ctrl on Windows and Linux.

• XML to JSON Converter — Convert XML to JSON with attributes and repeated tags handled, then explore the result in a tree.
• Response templates — generate dynamic JSON responses from request data and Faker.
• Fault injection — test how your app handles malformed JSON, error statuses and slow responses.
• All free developer tools