Free Online JSON Formatter & Validator
Input
Output
Use this free JSON formatter and validator to pretty print JSON, check syntax errors, and explore your data with an interactive tree view. Whether you are working on a quick API response or debugging a configuration file, this tool keeps your JSON readable and production-ready.
No data leaves your browser: everything runs locally for maximum privacy. Format JSON for documentation, validate before deployment, or minify for compact bundles with just a few clicks.
How to Use This JSON Formatter
- 1Paste or upload your JSON into the input panel.
- 2Choose the indent size you prefer and click “Format / Beautify” to pretty print JSON instantly.
- 3Toggle “Show Tree View” to inspect objects and arrays in a collapsible hierarchy.
- 4Use “Validate” to confirm the JSON is well-formed or “Minify / Compact” to shrink file size for production.
- 5Copy or download the formatted or validated JSON output for use in your project.
Features
Format & Beautify
Automatically apply consistent indentation and line breaks so you can pretty print JSON for quick reviews and code reviews.
Validate JSON
Run a JSON validator to catch syntax errors before you ship. Identify the exact line and character that caused the problem.
Minify & Compact
Remove whitespace and line breaks to create production-ready payloads that load faster and consume fewer bytes.
File Upload
Upload JSON files directly from your computer to edit and validate in seconds.
Copy & Download
Copy formatted JSON to your clipboard or download it as a `.json` file with one click.
Customizable
Choose the number of spaces or use tabs to match your project’s coding standards.
Tree View Explorer
Visualize complex objects in a collapsible tree and quickly inspect nested data structures without scrolling through raw text.
Line Numbers
Both the input and output editors include line numbers for precise debugging of long JSON files.
What Is JSON Formatting?
JSON (JavaScript Object Notation) is a lightweight data-interchange format used across web APIs, configuration files, and application state management. It represents data as key-value pairs, arrays, and nested objects while remaining human-readable.
Proper JSON formatting makes it easier to debug API payloads, collaborate with teammates, and avoid common JSON errors like missing commas or unescaped characters. A JSON validator ensures your data is syntactically correct before it reaches production systems.
Developers working with JavaScript, Python, Java, and many other languages rely on JSON to transfer structured data. Tools that combine JSON formatting and validation streamline everyday workflows, especially when comparing JSON vs. XML or working with large responses.
JSON Formatter FAQs
Is this JSON formatter safe to use?
Yes. The formatter, validator, and tree view run entirely in your browser. Your JSON data is never uploaded or stored on any server.
Does this tool save my data?
No. Once you refresh the page or close the tab, your input is cleared. For privacy, nothing is persisted or cached beyond your session.
Can I use this as a JSON validator?
Absolutely. Click “Validate” to confirm your JSON is well-formed. If an error exists, you’ll receive a helpful message pointing to the issue.
Can I pretty print JSON from an API response?
Yes. Paste the response into the input area, choose your indent size, and click “Format / Beautify.” You can also enable the tree view to drill into nested keys.
Is there a way to minify JSON outputs?
Use the “Minify / Compact” button to remove whitespace and line breaks, producing a minimized JSON string ideal for production builds.