JSON Formatter & Beautifier — Pretty Print JSON Online
Our free JSON Formatter instantly beautifies and validates any JSON string, turning minified or messy data into clean, readable output. Simply paste your raw JSON, choose your preferred indentation, and get a properly formatted result in seconds. Whether you're a developer debugging an API response or a data analyst reviewing a config file, this tool makes JSON easy to read and understand.
Paste raw, minified, or malformed JSON to format and validate it.
Choose how many spaces (or a tab) to use for each indentation level.
Enable to sort all object keys in alphabetical order.
Your results will appear here
How to Use This Calculator
1. Paste your raw, minified, or potentially malformed JSON into the input box. 2. Select your preferred indentation size — 2 spaces (most common), 4 spaces, or a tab character. 3. Optionally check 'Sort Keys Alphabetically' to reorder all object keys for easier scanning. 4. Click 'Calculate' or 'Format' to instantly see your prettified JSON along with validation status, character count, line count, and total key count. 5. Copy the formatted output from the result box and use it in your project, documentation, or debugging session.
What Is JSON Formatting?
JSON (JavaScript Object Notation) is a lightweight, human-readable data interchange format used extensively in web APIs, configuration files, and databases. When JSON is transmitted over a network, it is often minified — stripped of all whitespace — to reduce payload size. While efficient for machines, minified JSON is nearly impossible for humans to read at a glance.
JSON formatting (also called beautifying or pretty-printing) re-inserts consistent whitespace, newlines, and indentation to restore a hierarchical, readable structure without altering the underlying data.
How Does the Formatter Work?
The formatting process follows three steps:
- Parse: The raw JSON string is parsed using
JSON.parse(). If the string is not valid JSON, this step throws an error, and the tool reports the exact issue. - Transform (optional): If key sorting is enabled, all object keys are recursively sorted alphabetically before re-serialization.
- Serialize: The parsed JavaScript object is converted back to a string using
JSON.stringify(obj, null, indent), whereindentis your chosen indentation character.
Indentation Options
Indentation style is largely a matter of team convention:
- 2 Spaces: The most popular choice in JavaScript/Node.js projects and style guides like Airbnb's.
- 4 Spaces: Preferred in Python communities and many enterprise environments.
- Tab: Uses a single tab character per level, allowing each developer to configure their editor's tab width independently.
JSON Validation
A valid JSON document must follow strict rules: strings must be double-quoted, trailing commas are not allowed, and keys must be strings. This tool validates your input and displays a clear error message if any rule is violated, helping you pinpoint and fix issues quickly.
Common JSON Errors
- Using single quotes instead of double quotes for strings or keys.
- Leaving trailing commas after the last element in an array or object.
- Using
undefinedas a value (not permitted in JSON — usenullinstead). - Unescaped special characters inside string values.
- Missing or mismatched braces and brackets.
Key Sorting
Sorting keys alphabetically is useful when comparing two JSON objects side by side, reviewing diffs in version control, or enforcing consistency across configuration files. Note that JSON itself does not guarantee key order, but most modern parsers preserve insertion order, and most serializers will output keys in the order they appear in the object.