JSON Formatter & Validator
Format, prettify and validate JSON instantly in your browser
About JSON Formatter
Uses native JSON.parse and JSON.stringify. Everything runs in your browser — no data is sent to any server.
How to Use This Tool
- Paste your raw, minified, or malformed JSON into the input textarea.
- Click "Format" to instantly pretty-print the JSON with proper indentation and syntax highlighting.
- If the JSON is invalid, an error message shows the exact line and character position of the problem.
- Click "Copy" to copy the formatted JSON or "Minify" to compress it back into a single line.
Common Use Cases
- Debugging API responses that are returned as a single unreadable line by inspecting the structure.
- Validating JSON configuration files for applications before deployment.
- Formatting JSON data before pasting it into documentation, README files, or Confluence pages.
- Minifying JSON to reduce payload size before sending it over a network.
- Exploring nested JSON structures from third-party APIs to understand their schema.
Frequently Asked Questions
What is the difference between formatting and validating JSON?
Formatting (pretty-printing) adds indentation and newlines to make JSON human-readable without changing its data. Validation checks that the JSON syntax is correct — proper use of quotes, commas, brackets, and types — and reports errors if it is not.
What are common JSON syntax errors?
The most frequent mistakes are: trailing commas after the last array element or object property, using single quotes instead of double quotes for strings, unquoted property keys, and missing or extra brackets/braces.
What indentation level is used for formatting?
The formatter uses 2-space indentation by default, which is the most common standard for JSON used in web development. This matches the output of JSON.stringify(obj, null, 2) in JavaScript.
Is my JSON data sent to a server?
No. Formatting and validation run entirely in your browser using JavaScript's built-in JSON.parse() and JSON.stringify(). Your data never leaves your device.