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JSON Formatter

JSON & Data Format · Free Online Tool

Format, validate, and minify JSON.

By CoderNewbie TeamLast updated: 2026-09-20

Indent:

Input116 chars

Output

0 chars

Click "Format" to beautify your JSON...

Beautify

Format messy JSON into readable, indented structure with your preferred indent size.

Minify

Compress JSON by removing whitespace — perfect for production payloads.

Validate

Check if your JSON is valid and get clear error messages with location hints.

How to Use JSON Formatter

1Paste your input data (JSON, CSV, XML, YAML, etc.) into the input field.
2The tool automatically processes and validates your data.
3Review the converted output in the result panel.
4Copy or download the converted result.

Features

✓100% free — no signup, no subscription, no ads
✓Runs entirely in your browser — data never leaves your device
✓Fast and lightweight — instant results
✓Cross-platform — works on desktop, tablet, and mobile

What is JSON Formatter?

JSON (JavaScript Object Notation) is a lightweight data-interchange format defined by RFC 8259. It uses human-readable text to represent objects, arrays, and primitive values. A JSON Formatter beautifies minified JSON by adding indentation and line breaks, making it readable for debugging and inspection.

How does JSON Formatter work?

The parser tokenizes the JSON string, validates syntax according to RFC 8259, and builds an in-memory tree. The formatter then serializes the tree back to text with configurable indentation (2 or 4 spaces). Syntax errors are reported with line and column numbers.

Common Use Cases

✓REST API debugging — inspect request/response payloads
✓Configuration files — validate and beautify JSON config
✓NoSQL databases — review MongoDB/CouchDB documents
✓Log analysis — format JSON log entries for readability

JSON vs XML

JSON is lighter and faster to parse than XML. XML supports attributes and namespaces; JSON only has objects and arrays. JSON maps directly to most programming language data structures, making it the default for modern APIs. XML remains common in enterprise/SOAP environments.

Security & Privacy

This tool runs entirely in your browser — your JSON data is never uploaded. Be cautious with JSON containing sensitive data (tokens, passwords). JSON itself has no security model; always use HTTPS for transport and validate input on the server.

Technical Details

Standard: RFC 8259 / ECMA-404. Data types: string, number, boolean, null, array, object. Numbers are double-precision IEEE 754. Strings must be UTF-8. Keys must be double-quoted strings. Trailing commas are invalid. Comments are NOT supported (use JSONC or JSON5 for comments).

Frequently Asked Questions

Why does my JSON have a trailing comma error?

RFC 8259 forbids trailing commas. Remove the comma after the last item in objects and arrays.

Can JSON contain comments?

Standard JSON (RFC 8259) does not support comments. Use JSONC or JSON5 if you need comments. Most parsers will reject comments.

What is the maximum JSON size?

The spec sets no limit, but browsers and servers impose practical limits (typically 1-100MB). Very large JSON can cause memory issues; consider streaming parsers for big data.