Developer tools
JSON Formatter

JSON formatter and validator

Paste messy or minified JSON and get clean, indented output instantly. If the JSON is broken, CodeForge points to the exact line and column and explains the problem in plain English. Everything runs on your device — nothing is uploaded.

Open JSON Formatter — free Get the Windows app

Free in your browser — no sign-up. Install from the Microsoft Store to use it offline on Windows 10 and 11.

How to use it

Open the JSON Formatter and paste your JSON, or open a .json file.
Press Ctrl+Enter to format. Pick a different indent size if you don’t want 2 spaces.
Copy the result with Ctrl+Shift+C, or use Minify, Sort keys A–Z or Convert → YAML.

Example

Input

{"id":42,"name":"Ada Lovelace","roles":["admin","editor"],"active":true}

Formatted

{
  "id": 42,
  "name": "Ada Lovelace",
  "roles": [
    "admin",
    "editor"
  ],
  "active": true
}

Features

Validation with exact positions — syntax errors show the line, the column and a plain-English hint, such as a missing comma or quote.
Format or minify — pretty-print with your chosen indent size, or compress JSON to a single line for payloads and config files.
Sort keys A–Z — normalise key order so two documents are easy to compare.
JSON to YAML — convert in one click, with strings quoted wherever YAML needs it.
JSON to TypeScript — generate an interface for the root object for free. PRO adds nested types and nine more languages.
Optional AI — explain an unfamiliar payload or generate a JSON Schema with AI credits. Only the JSON you send with an AI action leaves your device.

Frequently asked questions

Is my JSON uploaded to a server?

No. Formatting, validation, minifying, key sorting and YAML conversion all run in your browser or in the Windows app. Data only leaves your device if you click one of the optional AI actions.

Why does my JSON fail to validate?

The usual culprits are trailing commas, single quotes instead of double quotes, unquoted keys and comments — none of which standard JSON allows. CodeForge shows the line and column where parsing stopped, so you can go straight to the problem.

Is there a file size limit?

There is no upload limit, because nothing is uploaded. Very large files are limited only by your device’s memory.

Is the JSON formatter free?

Yes. Formatting, validation, minifying, key sorting, YAML conversion and root-level TypeScript generation are free. Pro is optional.

One workspace for all of it

JSON Formatter is one of 18 developer tools in CodeForge — alongside a JSON formatter, JWT decoder, regex tester, UUID and hash generators, and more. Press Ctrl+K to jump to any of them.