Advanced JSON Formatter, Viewer & Validator
Format, validate and explore JSON like a pro. This advanced JSON formatter pretty-prints your JSON, highlights syntax, shows a collapsible tree view and detects errors instantly – ideal for debugging API responses, configuration files and structured data.
Input JSON
Output / JSON Viewer
Advanced Settings
Online JSON Formatter & Tree Viewer for Developers
This advanced JSON formatter is built for modern web and backend developers who work with REST APIs, GraphQL, log files, configuration files and any JSON-based data. Paste raw JSON on the left and see a clean, pretty-printed view on the right – or switch to a collapsible JSON tree viewer for deeper inspection. All processing happens securely in your browser.
What can this JSON formatter do?
- Pretty print JSON: Format messy one-line JSON into readable, indented code.
- Validate JSON: Detect syntax errors such as missing commas, invalid quotes and mismatched brackets.
- Minify JSON: Remove unnecessary whitespace to create compact JSON for production, storage or network transfer.
- Tree view / JSON explorer: Expand and collapse nested objects and arrays for easier navigation.
- Syntax highlighting: Keys, strings, numbers, booleans and null are coloured like a code editor.
Common use cases for the JSON formatter
- Debugging REST API responses
- Analysing JSON logs or analytics payloads
- Editing configuration files such as
config.json - Converting between CSV, JSON and other data formats
- Preparing JSON examples for documentation and tutorials
Related developer tools on ToolsHiveNow
- CSV to JSON Converter – convert spreadsheet data into JSON.
- HTML Encoder – safely encode JSON for HTML attributes.
- Base64 Encoder – encode JSON strings for transport.
- Markdown Previewer – format documentation for your APIs.
Frequently Asked Questions
How does the JSON tree view work?
The JSON tree viewer parses your JSON into objects and arrays, then renders a collapsible tree. You can click on the arrows next to any object or array to expand or collapse nested levels, making it easier to explore deeply nested data.
Is my JSON data uploaded or stored anywhere?
No. All formatting and validation happens directly in your browser using JavaScript. Your JSON never leaves your device, which is ideal for sensitive or private API responses.
Can this JSON formatter handle large files?
Yes, the tool is optimized to handle fairly large JSON payloads. However, performance may depend on your device and browser limits. For extremely large logs, consider formatting chunks of data.
What’s the difference between formatting and minifying JSON?
Formatting (pretty printing) adds line breaks and indentation so JSON is human-readable. Minifying removes all extra whitespace to reduce file size, which is better for production and network transfer.