Developer tools / JSON

JSON Formatter & Validator

Clean up messy JSON, catch syntax errors, and explore nested data without sending anything to a server.

Indent
InputJSON
{
  "project": "Practical Tool Lab",
  "active": true,
  "tools": [
    "JSON Formatter",
    "Timestamp Converter"
  ],
  "owner": {
    "name": "Xiao & Mei",
    "location": "Shanghai"
  }
}
Valid JSON
180 B6 keys6 valuesDepth 2Processed locally

Pinpoint errors

See a clear validation message with the exact line and column whenever possible.

Explore as a tree

Collapse deeply nested objects and arrays instead of scanning hundreds of lines.

Private by design

Formatting happens locally in your browser. Your JSON is never uploaded to us.

How to format JSON

  1. 1. Add your data. Paste JSON into the input editor or drop a .json file.
  2. 2. Fix any errors. The validator shows where parsing stopped so you can correct the source quickly.
  3. 3. Use the result. Format, minify, sort keys, inspect the tree, then copy or download the cleaned JSON.

Common use cases

When a JSON formatter saves time

Debug an API response

Paste a compact response from fetch, Postman, or your browser's network panel to spot a missing field or unexpected value.

Review configuration files

Make package, deployment, and app configuration files readable before committing them to source control.

Inspect webhook payloads

Expand nested event data and verify the keys your integration receives without sharing customer data with a third party.

Prepare JSON for a teammate

Sort keys and format a clean example that is easier to paste into a bug report, ticket, or documentation page.

JSON Formatter FAQ

Is my JSON uploaded?

No. Formatting, validation, sorting, and tree rendering run in your browser. Your input is not sent to a Practical Tool Lab server.

What does valid JSON require?

JSON requires double-quoted property names and strings, commas between items, and no trailing comma. The validator reports where parsing stopped when it finds a problem.

What is the difference between format and minify?

Formatting adds indentation and line breaks for people. Minifying removes unnecessary whitespace to reduce the size of a JSON payload.