How to Format & Validate
JSON Online Free
Prettify minified JSON, catch syntax errors instantly, and explore nested data — all in your browser with no server required.
Try the JSON FormatterWhy format JSON?
JSON (JavaScript Object Notation) is the universal data format for APIs, configuration files, and data storage. But JSON from API responses, log files, or database exports is often minified — compressed into a single unreadable line to save bandwidth. Trying to read or debug minified JSON is nearly impossible without a formatter.
A JSON formatter instantly transforms minified JSON into a properly indented, human-readable structure. It also validates your JSON, catching syntax errors that would cause API calls or parsers to fail — with precise error location so you can fix the issue immediately.
Step-by-step: format JSON in seconds
Open the JSON Formatter
Visit the free JSON Formatter tool. It works entirely in your browser — no server round-trips, no latency, no file size limits.
Paste your JSON
Paste raw, minified, or malformed JSON into the input panel. The formatter validates it in real-time as you type, highlighting the first syntax error found.
Choose indentation
Select 2-space, 4-space, or tab indentation. 2 spaces is the most widely used convention and produces compact yet readable output.
Copy the formatted output
Click Copy to grab the formatted JSON, or use Minify to collapse it back to a single line for transport. You can also download as a .json file.
Pro tips for working with JSON
Use the tree view for complex structures
The collapsible tree view makes navigating deeply nested JSON much easier than reading raw text. Expand only the nodes you need.
Fix errors before formatting
The validator shows the exact line and position of syntax errors. Common mistakes: trailing commas, single quotes instead of double, and unquoted keys.
Minify before sending in API requests
When including JSON in an API request body or storing in a database, minify it first to reduce size. Our formatter does both — prettify and minify.
Use JSON Path to extract values
If you need to extract a specific value from complex JSON (e.g. response.data[0].user.id), use the JSON Path feature to query without writing code.
Your data is never sent to any server
The formatter processes JSON entirely in your browser using JavaScript. API responses with auth tokens, database credentials, private configuration files, and any other sensitive JSON data stays completely private on your device.
Frequently asked questions
What is JSON formatting?
JSON formatting (or 'prettifying') adds indentation and line breaks to raw or minified JSON, making it human-readable. Minified JSON is a single line with no whitespace — efficient for machines but impossible to read without formatting.
What's the difference between formatting and validation?
Formatting changes the visual layout (indentation, line breaks) without changing the data. Validation checks whether the JSON is syntactically correct — properly quoted keys, no trailing commas, valid data types, etc.
Why does my JSON have a syntax error?
The most common JSON syntax errors are: trailing commas after the last item in an array or object (valid in JavaScript but not JSON), single quotes instead of double quotes, unquoted property keys, and undefined or NaN values (not valid JSON types).
Is it safe to format sensitive JSON (API keys, tokens)?
Yes — our formatter runs entirely in your browser. Your JSON is never sent to any server. API keys, JWTs, database credentials, and any other sensitive data stay on your device.
Can I format JSON from a URL or API response?
Yes — you can paste any JSON text, including copied API responses from browser DevTools, Postman, or curl output. The formatter handles any valid JSON regardless of where it came from.