JSON Formatter Online

Format JSON for Easier Reading

Compact JSON is useful for sending data, but it is awkward to inspect when an entire response sits on one line. This JSON formatter adds line breaks and indentation so you can follow objects, arrays, and nested values. Paste text or open a .json file, choose an indentation style, and select Format JSON.

The output is shown as syntax-highlighted code or as an expandable tree. You can search keys and values in the tree, copy a matching property path, check basic size and structure statistics, then copy or download the formatted file. The guide below explains what each option does and where formatting needs extra care.

How to Use the JSON Formatter

1. Paste JSON into the input panel, select Open file, or drop a .json file into the input area. Use Sample if you want to try the controls with example data.
2. Choose 2 spaces, 4 spaces, or Tabs under Indentation.
3. Leave Sort keys A-Z off to keep the input's property order, or turn it on to sort object keys recursively.
4. Select Format JSON. If the input cannot be parsed, the status message reports an error and a line and column when available.
5. Review the result in Code or Tree view. Copy or download the output when it is ready.

Use Full screen for a wider workspace. In Tree view, search for a key or value, move between matches, expand or collapse nested branches, and copy the selected property's path. The statistics below the editors show input, formatted, and minified sizes, plus object-key count, array-item count, and maximum depth.

JSON Formatting Example

Here is a compact API-style object before and after formatting. The line breaks make it easier to see that retry is a nested object and that enabled is a Boolean.

Before formatting

{"service":"orders","retry":{"limit":3,"backoff":"exponential"},"enabled":true}

After formatting with two spaces

{
  "service": "orders",
  "retry": {
    "limit": 3,
    "backoff": "exponential"
  },
  "enabled": true
}

The values are easier to scan, but indentation is only a presentation choice. The JSON data is still intended to represent the same object.

What Does a JSON Formatter Do?

A JSON formatter, sometimes called a JSON beautifier or pretty printer, parses JSON text and writes it with consistent whitespace. The JSON syntax itself is defined in RFC 8259. Indentation shows which properties belong to each object and which values belong to each array. This makes formatted JSON easier to read in API responses, configuration files, logs, test fixtures, and code reviews.

Formatting is different from editing the data. It does not explain what a field means, check whether your application requires it, or repair malformed JSON. This formatter also offers an optional key-sorting setting; because sorting changes the text order, leave that setting off when you want to preserve the input order for review.

Choose an Indentation Style

Two spaces are a common choice for readable JSON in web projects. Four spaces create a wider indent that some teams prefer for configuration or examples. Tabs let an editor or viewer control how wide each indentation level appears. Pick the style that fits your project or team; changing indentation does not make JSON more or less valid.

For generated files or code reviews, use the same indentation consistently so unrelated whitespace changes do not make a diff harder to inspect.

What Does “Sort Keys A-Z” Change?

When enabled, Sort keys A-Z sorts object property names recursively. It does not sort array items. Sorting can make two documents easier to compare when their objects contain the same data in different property orders, but it changes the text and can create a large diff. Keep it off when you only want to add indentation or when preserving the original order is useful to your workflow.

The JSON standard describes objects as unordered collections, so property order is not a reliable way to express priority or sequence. If order matters to your application, represent that sequence as an array and check how the application handles the data. See RFC 8259, section 4.

Formatting, Validation, Minification, and Repair

These tools solve related but different problems:

This formatter needs valid JSON to produce output. If it reports a syntax error, use the JSON Validator to review the error details. For common JSON-like mistakes, JSON Repair can attempt a correction; inspect the result because a repair tool cannot know what you intended. Use the JSON Minifier when you want compact output, or the JSON Schema Validator to check required fields and value types.

Important Data Checks Before You Rely on the Output

Formatting is not always a byte-for-byte-preserving operation. This tool uses the browser's JavaScript JSON parser and serializer. The default format changes whitespace, and a number's written form may also change; for example, an exponent such as 1e2 can be written as 100.

JavaScript represents JSON numbers with its Number type, which cannot represent every integer exactly. Values outside the safe-integer range can lose precision when parsed and written again; see MDN’s Number.MAX_SAFE_INTEGER reference. If a value is an identifier, account number, or other exact digit string, consider storing it as a quoted string in the source data and check the output before using it. Exact decimal values also deserve care when precision matters.

Duplicate property names need attention too. RFC 8259 says object names should be unique and notes that duplicate-name handling varies between implementations. This formatter uses JavaScript JSON.parse, where the later value replaces the earlier one in the parsed object. The formatter cannot preserve both duplicate entries. See RFC 8259, section 4 and the MDN JSON.parse reference. Review such input before formatting if every occurrence matters.

With Sort keys A-Z enabled, object property order also changes. If you need to preserve the exact original text, use a text editor instead of formatting the input.

Limits and Large JSON Files

The formatter accepts input up to 50 MiB and handles nesting up to 500 levels. Tree view displays up to 10,000 nodes; if a document has more, the formatted code remains complete even though the tree view is limited. Large inputs may take longer to parse or render, depending on the device and browser.

The size statistics describe text size before or after formatting and the size of a compact serialization; they are not a guarantee of the final HTTP request size, since network headers, compression, and application behavior are separate.

Privacy and Local File Handling

The formatter's page code parses pasted JSON in the browser and reads a selected file with the browser's file-reading API. The formatter script does not send the input text to a server. This describes the formatter code on this page; for information about broader site data handling, review the Privacy Policy. Avoid placing passwords, tokens, private keys, or confidential records into an online tool unless you have confirmed that it meets your requirements.

Frequently Asked Questions

Related JSON Tools

Format readable JSON here, check syntax with the JSON Validator, inspect nested data with the JSON Viewer, or browse the JSON tools for conversion, comparison, and schema workflows.