Paste your JSON to instantly format, validate, minify, and explore it. Syntax-highlighted output, interactive tree view, key sorting, JSON stats, and one-click conversion to CSV and YAML.
What Is a JSON Formatter?
A JSON formatter takes raw, minified, or poorly structured JSON text and adds proper indentation, line breaks, and spacing to make it human-readable. It also validates the JSON syntax and highlights any errors so you can find and fix problems instantly.
JSON (JavaScript Object Notation) is used in almost every web application and API as the standard format for transferring data. When a server sends JSON in production, it strips all the whitespace to reduce file size. The result is a single line of tightly packed text that is nearly impossible for a human to read or debug. A JSON formatter reverses this process, presenting the same data in a structured, indented format where every key-value pair is visible at a glance.
Our formatter goes further than most free tools. It validates your JSON as you format it, highlighting the exact line and character where an error occurs. It builds an interactive tree view that lets you expand and collapse nested objects. It shows a statistics panel covering total keys, max depth, array and object counts, value type breakdown, and file size. It converts JSON to CSV and YAML. And it sorts keys alphabetically with one click.
Everything runs in your browser. Your JSON is never sent to any server and never stored anywhere. This makes the tool safe to use with API keys, database records, configuration files, and any other sensitive JSON data.
What Is JSON?
JSON stands for JavaScript Object Notation. It is a lightweight text format for storing and exchanging structured data. JSON uses key-value pairs organised into objects and arrays, written in a syntax that is easy for both humans to read and machines to parse. It is the most widely used data format for APIs, configuration files, and web applications.
JSON was introduced by Douglas Crockford in the early 2000s as a simpler alternative to XML for data exchange between servers and browsers. It was standardised as ECMA-404 and RFC 8259. Today it is supported natively in every major programming language and is the default response format for the vast majority of REST APIs.
A JSON document can contain six data types:
- String - text wrapped in double quotes:
"WritoryBuzz" - Number - integer or decimal:
2026or4.7 - Boolean - true or false:
true - Null - an empty value:
null - Object - a set of key-value pairs in curly braces:
{"key": "value"} - Array - an ordered list of values in square brackets:
[1, 2, 3]
A valid JSON document must use double quotes for all keys and string values, commas between items, no trailing commas, and no comments. These rules are where most JSON errors occur, and they are exactly what this validator checks for.
How to Use This JSON Formatter
The tool has several modes. Here is what each button and feature does.
Format / Beautify
Paste your JSON into the left panel and click Format. The tool parses your JSON, validates it, and produces an indented, readable version in the right panel with full syntax highlighting. If the JSON contains an error, the output panel shows the exact error message with the line and character position where the problem is.
Minify
Minify removes all whitespace, indentation, and line breaks from your JSON, producing the smallest possible version of the data. Use this before including JSON in a production API response, a configuration file, or anywhere file size matters. Minified JSON is identical in data to formatted JSON.
Validate
Validation checks whether your JSON is syntactically correct without reformatting it. The status badge below the input panel turns green for valid JSON and red for invalid. The error message tells you exactly what is wrong and where.
Sort Keys
Sort Keys alphabetically reorders all object keys in your JSON from A to Z at every level of nesting. This is useful for comparing two JSON objects, standardising the key order in configuration files, and making large JSON structures easier to navigate.
Fix / Repair
The repair function attempts to fix common JSON errors automatically: adding missing quotes around keys, removing trailing commas, fixing single quotes used instead of double quotes, and correcting simple syntax issues. It does not fix all errors but handles the most common ones.
Tree View
The interactive tree view shows your JSON as a collapsible hierarchy. Click any object or array node to expand or collapse it. This makes navigating deeply nested JSON structures much faster than reading raw text. The tree view shows the type and length of each value alongside the key name.
Convert to CSV
If your JSON contains an array of objects at the root level, the CSV converter extracts the keys as column headers and each object as a row. The resulting CSV is ready to open in Excel, Google Sheets, or any spreadsheet application.
Convert to YAML
YAML is a human-friendly data serialisation format widely used in configuration files, DevOps tools (Docker Compose, Kubernetes), and CI/CD pipelines. The YAML converter produces clean, properly indented YAML from any valid JSON input.
Common JSON Errors and How to Fix Them
Most JSON validation failures come from a small set of common mistakes. Here is what to look for when your JSON is rejected.
| Error | Example of the Problem | Correct Version |
|---|---|---|
| Trailing comma | {"a": 1, "b": 2,} | {"a": 1, "b": 2} |
| Single quotes | {'key': 'value'} | {"key": "value"} |
| Unquoted key | {key: "value"} | {"key": "value"} |
| Missing comma | {"a": 1 "b": 2} | {"a": 1, "b": 2} |
| Comment in JSON | {"a": 1 // comment} | Remove comments — JSON does not support them |
| Undefined value | {"a": undefined} | {"a": null} |
| Unclosed bracket | {"a": [1, 2, 3} | {"a": [1, 2, 3]} |
| Extra data after root | {"a": 1}{"b": 2} | Wrap in array: [{"a": 1}, {"b": 2}] |
Use the Fix / Repair button to automatically correct trailing commas, single quotes, and unquoted keys. For other errors, the validator will point you to the exact line and position where the problem is.
JSON vs XML vs YAML — When to Use Each
| Format | Best For | Human Readable | Comments | File Size |
|---|---|---|---|---|
| JSON | APIs, web apps, data exchange | Good | Not supported | Small |
| XML | Enterprise systems, document storage | Verbose | Supported | Large |
| YAML | Config files, DevOps, CI/CD pipelines | Very good | Supported | Small |
| CSV | Tabular data, spreadsheets | Good | Not supported | Very small |
JSON is the right choice for API responses and data transfer between applications. YAML is better for configuration files because it supports comments and is easier to write by hand. CSV is the best choice when your data is a flat table that needs to be opened in a spreadsheet. Our tool converts JSON to both YAML and CSV with a single click.
JSON Formatting for Developers — Key Concepts
Indentation standards
The two most common JSON indentation standards are 2 spaces and 4 spaces. Most JavaScript and web projects use 2 spaces. Python and Java projects often use 4 spaces. Both are equally valid. The tool supports 2 spaces, 4 spaces, and tab indentation. Choose based on the standard used by the project you are working on.
JSON in API development
When you are building or consuming a REST API, a JSON formatter is an essential debugging tool. API responses arrive minified. Pasting the raw response into a formatter lets you inspect the structure, find the fields you need, and verify that the response matches the expected schema. The tree view and key paths extractor are especially useful for navigating deeply nested API responses.
JSON in configuration files
Many applications use JSON for configuration: VS Code settings, package.json, tsconfig.json, and countless custom config files. These files must be perfectly valid JSON. A single trailing comma or missing bracket breaks the entire application. Use the validator here before committing a configuration change.
JSON and schema validation
JSON Schema is a standard for defining the structure, types, and constraints that a JSON document must satisfy. While this tool validates JSON syntax (is it valid JSON?), a separate JSON Schema validator checks whether the data conforms to a specific structure (does this JSON match the expected API contract?). Syntax validation is always the first step before schema validation.