JSON / JSON5 Formatter
What is the JSON / JSON5 Formatter?
If you are looking for an online json beautifier or a handy json file viewer, this tool is the perfect answer to 'how to format json'. Unlike standard parsers, if you're wondering about the 'difference between json and json5' or need a 'json with comments parser', this tool fully embraces the JSON5 specification (single quotes, trailing commas) and offers a 'Preserve Comments (JSONC)' mode. Formatting config files like tsconfig.json has never been easier.
How to Use the Online JSON Formatter?
- Paste your code to see immediately 'is my json valid'—the built-in json parser online will catch any issues instantly.
- Select your output format: 'Standard JSON', 'JSON5 Specification', or 'Preserve Comments (JSONC)'.
- Adjust the indentation (2 spaces, 4 spaces, or Tab) to format json exactly how you like it.
- Click 'Minify' if you need to 'compress json into one line' to reduce payload size and remove whitespace.
Common Use Cases
- Validate JSON Online & Fix Errors: Struggling with a 'json syntax error fix'? Paste your broken response from a RESTful API to instantly locate missing commas, brackets, and format it into a clean hierarchy.
- JSON with Comments Parser: Modern projects use JSON files with comments (e.g., VS Code settings). Use our JSONC mode to safely beautify these files without destroying explanatory comments.
- Compress JSON Into One Line: Before deploying data to production, utilize the 'Minify' feature to strip out unnecessary spaces and line breaks, optimizing network bandwidth.
- Universal JSON File Viewer: A lightweight and reliable json file viewer right in your browser, perfect for reading massive configuration payloads securely.
Why Choose Our JSON Tool?
- 100% Privacy Protection: All formatting and parsing happens locally in your browser. Your sensitive JSON data is never uploaded or sent to any server.
- Advanced JSON5 & JSONC Support: Outperforms basic formatters by embracing single quotes, trailing commas, and retaining comments perfectly.
- Fully Customizable: Easily tweak output indentation styles, swapping between 2 spaces, 4 spaces, or tab indentation to match your exact coding standards.
Frequently Asked Questions
What is JSON?
JSON (JavaScript Object Notation) is a lightweight data interchange format that is easy for humans to read and write, and easy for machines to parse and generate. It is based on a subset of JavaScript but is language-independent and supported by virtually all modern programming languages.
What is JSON5 and how is it different from standard JSON?
JSON5 is a syntax extension to standard JSON designed to make it more human-writable and readable. Unlike standard JSON's strict requirements, JSON5 supports single-line and multi-line comments, single quotes for strings, unquoted keys, trailing commas in objects and arrays, hexadecimal numbers, and special numbers like Infinity and NaN.
Can I format JSON while preserving comments (JSONC)?
Yes! Our tool features a dedicated 'Preserve Comments (JSONC)' mode. Utilizing a lossless syntax tree parser, it formats and indents your JSON code while perfectly keeping all single-line `//` or block-level `/* ... */` comments intact. This is extremely useful for files like tsconfig.json or settings.json.
Why can JSON have comments?
Strictly speaking, the standard JSON specification (RFC 8259) does not support comments of any kind in order to keep data interchange pure and efficient. However, in modern development, JSON is widely used for configuration files (like VS Code settings, tsconfig.json, etc.), where developers desperately need comments to explain configuration options. This necessity led to the creation of extended specifications like JSONC (JSON with Comments) and JSON5. With our tool, you can safely parse and format these commented JSON files without throwing syntax errors.
What's the Difference Between JSON and XML?
JSON is more compact and easier to read than XML. JSON uses key-value pairs and arrays, while XML uses tags. JSON is typically faster to parse and has become the preferred format for web APIs. XML, however, supports attributes and namespaces, making it more suitable for complex document structures.
What Are Common JSON Syntax Errors?
Common JSON errors include: trailing commas after the last element (unsupported in standard JSON but supported in JSON5), using single quotes instead of double quotes, unquoted property names, and containing comments. Our online validator highlights these errors and helps you fix them in one click.
What Data Types Does JSON Support?
JSON supports six data types: String (text in double quotes), Number (integer or floating-point), Boolean (true or false), Null (empty value), Object (key-value pairs in curly braces), and Array (ordered list in square brackets). Note that JSON does not support undefined, functions, or dates natively.
How to Parse JSON in Different Programming Languages?
Here are examples of parsing JSON in various languages:
JavaScript
const obj = JSON.parse(jsonString);Python
import json
data = json.loads(json_string)Go
json.Unmarshal([]byte(str), &v)When Should I Format vs Minify JSON?
Format (prettify) JSON when you need to read, debug, or edit the data manually. Minify JSON when transmitting data over networks or storing in databases to reduce file size and improve performance. Minified JSON removes all unnecessary whitespace and newlines.
Why is JSON the Standard for Web APIs?
JSON became the standard for web APIs because it's lightweight, human-readable, and natively supported by JavaScript (the language of web browsers). It's simpler than XML, faster to parse, and works seamlessly with modern frontend frameworks like React, Vue, and Angular.
How to Validate JSON Data?
You can validate JSON using online tools like this formatter, or programmatically using try-catch blocks when parsing. For schema validation, use JSON Schema to define the structure your JSON should follow. Many IDEs also have built-in JSON validation features.