JSON Formatter — Free Online JSON Formatter, Validator & Prettifier

Best JSON Formatter — Why Developers Choose This Tool

The best JSON formatter for developers combines speed, privacy, and advanced features in one place. Unlike cloud-based formatters that upload your JSON to a server, our tool processes entirely in your browser using the native JavaScript V8 engine — the same engine that powers Node.js.

JSON Formatter and Validator — Fix Syntax Errors Instantly

A JSON formatter and validator does two distinct jobs: it formats (prettifies) your JSON for readability, and it validates that your JSON strictly follows the JSON specification. Switch to "Validate" mode above to get detailed error reporting including the exact line and column number of any syntax problem.

The most common JSON syntax errors caught by our validator:

String to JSON Formatter — Convert Raw Text to Valid JSON

String to JSON formatter refers to the process of taking a stringified or escaped JSON string and converting it to proper JSON. This commonly happens when API responses double-encode JSON (wrapping JSON in a JSON string), or when copying from logs where quotes are escaped.

• Escaped string: {"name":\"John\",\"city\":\"LA\"} — paste into Format mode to automatically unescape and prettify
• Stringified JSON: "{\"key\":\"value\"}" — the outer quotes tell JSON.parse to treat the content as a string; paste and format to see the nested structure
• Text to JSON: For converting plain CSV or key-value text to JSON, paste the raw text and use the format mode — the validator will show exactly what structure is needed
• URL-encoded JSON: Decode first (use a URL decoder), then paste the decoded string into our formatter

XML to JSON Formatter — Convert XML Files Instantly

Our XML to JSON formatter converts any valid XML document to a JSON object using standard rules: XML element names become keys, text content becomes values, and XML attributes are prefixed with @. Sibling elements with the same tag name are automatically grouped into JSON arrays.

<users>
  <user id="1">
    <name>Alice</name>
    <role>Admin</role>
  </user>
  <user id="2">
    <name>Bob</name>
    <role>Editor</role>
  </user>
</users>

{
  "user": [
    {
      "@id": "1",
      "name": "Alice",
      "role": "Admin"
    },
    {
      "@id": "2",
      "name": "Bob",
      "role": "Editor"
    }
  ]
}

This Easy KD use case is common when integrating legacy systems (SOAP APIs, RSS feeds, Salesforce exports) with modern REST/JSON-based services. Use the "XML → JSON" tab above — paste your XML and get clean, formatted JSON output instantly.

JSON Formatter Chrome Extension — Format JSON in Browser

A JSON formatter Chrome extension automatically reformats raw JSON when you visit a JSON URL directly in the browser (e.g., an open API endpoint or a localhost:3000/api/data response). Without an extension, Chrome displays flat, unformatted text.

For one-off formatting without installing any extension, our online formatter above works in any browser tab — paste your JSON and get instant output with copy and download support. No permissions required.

Notepad++ JSON Formatter — Plugin Setup Guide

The Notepad++ JSON formatter is available through two free plugins from the Plugin Admin. Here's the exact setup for each:

1. Open Plugin Admin: Launch Notepad++ → click Plugins in the menu bar → select Plugins Admin…
2. Install JSTool: Search for "JSTool" → check the box → click Install → restart Notepad++. After restart, select your JSON text, then: Plugins → JSTool → JSFormat (or press Ctrl+Alt+M).
3. Alternatively, install JSON Viewer: Search "JSON Viewer" in Plugin Admin → Install. This adds a side panel with a collapsible tree view — ideal for large nested JSON files.
4. For auto-formatting on paste: JSTool can be triggered via a macro if you need it. Create a macro (Tools → Macro → Start Recording) that runs JSFormat, then assign a shortcut.

Quick comparison: JSTool formats in-place (edits the file directly) while JSON Viewer shows a read-only tree in a side panel. Use JSTool for editing; use JSON Viewer for reading/debugging. Both are Easy KD ranking opportunities since most pages only mention one or the other.

JSON Formatter Features — Minify, Validate, Tree View & More

Our online json formatter is built on the browser's native JSON.parse() and JSON.stringify() APIs — the fastest possible implementation. Here's what each mode does:

Minify tip for production: Minified JSON reduces file size by removing all whitespace. A typical prettified JSON config file of 8 KB minifies to 4–5 KB — a meaningful saving when sending JSON payloads at scale (millions of API calls per day).