Developer tool
JSON Formatter
Validate, pretty-print, minify, and optionally sort pasted JSON in your browser before using it in code, documentation, API debugging, tests, or configuration files. Formatting changes whitespace and layout, while valid JSON values remain represented by the same data.
Characters
265
Lines
18
Bytes
265
Validation
Formatted Output
Valid JSON
Objects
4
Arrays
1
Keys
10
Overview
What Is a JSON Formatter?
A JSON Formatter makes valid JSON easier to read by parsing the input and serializing it with the selected whitespace, indentation, and line-break style. Developers use formatted JSON when reviewing API responses, configuration files, fixtures, logs, and debugging data.
This page validates pasted JSON syntax, formats it with 2 spaces, 4 spaces, or tabs, minifies it when requested, optionally sorts object keys, and provides readable counts for objects, arrays, keys, characters, lines, and bytes.
Features
JSON Formatting Features
JSON text input
Paste JSON directly into the input area.
Syntax validation
Invalid JSON shows the JSON.parse error and prevents formatted output.
Pretty printing
Choose 2 spaces, 4 spaces, or tabs for readable indentation.
Minification
Choose Minify to remove pretty-print indentation.
Key sorting
Sort object keys recursively when the checkbox is enabled.
Statistics
View character, line, byte, object, array, and key counts.
Copy
Copy the current formatted output to the clipboard.
Clear and sample
Clear the workspace or reload the built-in sample JSON.
Method
How JSON Formatting Works
The formatter parses the input with JSON.parse. If parsing succeeds, it optionally sorts object keys recursively, then serializes the result with JSON.stringify using the selected indentation mode. If parsing fails, the output is cleared and the parser error is displayed.
Pretty-printed JSON uses whitespace to improve readability. Minified JSON removes the extra formatting whitespace. Neither mode is the same as gzip, Brotli, or another compression algorithm.
Syntax
JSON Syntax Explained
Objects
Objects use curly braces and contain string property names with values.
Arrays
Arrays use square brackets and contain ordered values.
Values
JSON values can be objects, arrays, strings, numbers, true, false, or null.
Strings
Strings and object names use double quotes, not single quotes.
Whitespace
Whitespace outside strings can be insignificant; whitespace inside strings is data.
Escaping
Quotation marks, backslashes, control characters, and Unicode escapes have JSON escaping rules.
Validation
JSON Validation and Errors
This formatter performs JSON syntax validation as part of parsing. It does not perform JSON Schema validation, application-level validation, data cleaning, or malformed JSON repair. Error messages come from the underlying parser and may mention unexpected tokens or positions depending on the browser.
A valid formatted document can still contain data that is wrong for your application. Formatting and syntax validation do not prove that values match a business rule, API contract, or database schema.
Comparison
Pretty-Printed vs Minified JSON
| Mode | Output | Use |
|---|---|---|
| 2 spaces | Readable indentation with two spaces | Code review and common style guides |
| 4 spaces | Readable indentation with four spaces | Workflows preferring wider indentation |
| Tabs | Readable indentation using tab characters | Projects that use tabs |
| Minify | No pretty-print indentation | Compact transfer or storage text |
Examples
Common JSON Formatter Examples
API response
Pretty-print compact API JSON so nested data is easier to inspect.
Debugging
Format JSON while tracing application or integration issues.
Configuration
Review JSON configuration files with consistent indentation.
Development fixtures
Format mock payloads before adding them to tests or documentation.
Code review
Sort keys or pretty-print JSON to make structural changes easier to read.
Workflow
How to Use the JSON Formatter
- Paste JSON into the input area.
- Choose 2 spaces, 4 spaces, tabs, or minified output.
- Enable Sort object keys if recursive key sorting is useful for your workflow.
- Review validation status, formatted output, and JSON statistics.
- Copy the formatted JSON, clear the workspace, or reload the sample.
Advantages
Benefits
- Improves readability of nested JSON structures.
- Helps inspect API responses, configuration files, and sample payloads.
- Offers pretty printing, minification, and recursive key sorting.
- Uses a browser-based workflow with no extra dependency added to the site.
- Provides copy and statistics for quick development tasks.
Boundaries
Limitations
- File upload, drag-and-drop, download, syntax highlighting, and tree view are not implemented.
- Formatting does not repair malformed JSON.
- JSON Schema validation and application-specific validation are not included.
- Duplicate object names should be avoided because parsing can resolve them before formatting.
- Pretty-printed JSON can be larger than compact JSON because it contains extra whitespace.
- Very large JSON input may be limited by browser memory and rendering behavior.
Guidance
Tips for Best Results
- Use valid JSON with double-quoted strings and property names.
- Check commas between object properties and array elements.
- Choose the indentation mode that matches your project or document style.
- Use minified output only when compact text is more useful than readability.
- Remember that whitespace inside string values is data and should be preserved.
Avoid
Common Mistakes
- Using single quotes instead of JSON double quotes.
- Leaving trailing commas in objects or arrays.
- Assuming formatting fixes invalid JSON automatically.
- Confusing JSON syntax validation with JSON Schema validation.
- Assuming property ordering is universally meaningful in every JSON workflow.
Questions
FAQ
What is a JSON Formatter?
A JSON Formatter parses JSON text and serializes it with readable indentation, compact minified output, or the selected formatting settings.
How do I format JSON online?
Paste valid JSON into the input area, choose an indentation mode, and review the formatted output.
What is JSON pretty printing?
Pretty printing adds line breaks and indentation so nested JSON objects and arrays are easier to read.
Does formatting JSON change the data?
Formatting changes presentation. For valid JSON, values are parsed and serialized without intentionally changing the represented data.
Does this formatter validate JSON?
Yes. The page uses JSON.parse, so invalid JSON prevents output and shows the parser error message.
What is the difference between JSON formatting and JSON validation?
Formatting changes whitespace and layout. Syntax validation checks whether the text follows JSON grammar.
Can I format a JSON file?
This implementation does not include file upload. Open the file elsewhere and paste its JSON text into the input area.
Can I customize indentation?
Yes. Choose 2 spaces, 4 spaces, tabs, or minified output.
Can I minify JSON?
Yes. Select Minify to serialize the JSON without pretty-print indentation.
Does it sort JSON keys?
Yes, if Sort object keys is enabled. Sorting is applied recursively before serialization.
Does JSON allow comments?
No. Standard JSON does not allow comments, and this formatter does not add comment support.
Can I use single quotes in JSON?
No. JSON strings and object names must use double quotes.
Does JSON formatting change property order?
With sorting disabled, the formatter serializes the parsed object in its current property order. With sorting enabled, object keys are sorted recursively.
What happens when JSON has duplicate object names?
This formatter uses JSON.parse before serialization. Duplicate names should be avoided because parser behavior can vary; in this browser-based workflow, the parsed value is what gets formatted.
Can I copy formatted JSON?
Yes. Use Copy JSON to copy the current formatted output.
Can I download formatted JSON?
No. This implementation provides copy, clear, and sample controls, but no download button.
Is the JSON Formatter free?
Yes. This is a free browser-based JSON formatting tool.
Does the JSON Formatter work on mobile devices?
Yes. It uses standard browser text areas, checkboxes, segmented controls, and buttons, so behavior depends on the mobile browser.
Is my JSON data uploaded to a server?
The formatter runs in your browser and does not intentionally upload pasted JSON data.
More Tools
Related Tools
Terms
Glossary
JSON
JavaScript Object Notation, a text syntax for structured data.
JSON Object
A collection of string names and values inside curly braces.
JSON Array
An ordered list of values inside square brackets.
JSON Value
An object, array, string, number, boolean, or null.
JSON Parsing
Reading JSON text and constructing the represented value.
JSON Serialization
Producing JSON text from a structured value.
Pretty Printing
Adding indentation and line breaks for readability.
Minification
Removing unnecessary formatting whitespace for compact output.
Whitespace
Spaces, tabs, and line breaks outside strings that can help readability.
Indentation
Leading whitespace that shows nesting depth.
Escape Sequence
A sequence used to represent special characters inside strings.
Syntax Error
An error caused by text that does not follow JSON grammar.
JSON Validation
Checking whether JSON text follows JSON syntax.
JSON Schema
A separate vocabulary for describing and validating JSON data shapes.
Nested Object
An object inside another object or array.
Data Structure
An organized arrangement of values.
Sources
References
Transparency & Verification
Educational Disclaimer
This tool formats JSON according to its implemented parsing, optional sorting, and serialization methods. Formatting primarily changes whitespace, indentation, and presentation for typical valid input. Parsing and serialization can normalize the text, especially when duplicate object names are present. It does not validate JSON Schema or business rules. Verify important JSON data and application-specific requirements before using formatted output in production.
Calculations and transformations execute locally on your machine with full offline support. Always verify critical results.
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