JSON Formatter & Validator

Beautify, minify, and validate JSON. Everything runs in your browser, so your data never leaves the page.

About this JSON formatter

This is a free online JSON formatter and validator. Paste any JSON document into the input panel and you'll get a pretty-printed, syntax-checked version in the output panel. If the input is invalid, the tool tells you exactly where the parser failed.

Features

  • Format any JSON with 2, 4, or tab indentation.
  • Minify JSON to remove all whitespace for transport.
  • Validate with precise line and column error reporting.
  • Sort keys alphabetically for deterministic diffs.
  • Copy the result or download it as a .json file.

Privacy

Your JSON never leaves your browser. The entire tool runs locally as JavaScript on this page, so you can safely paste sensitive payloads, API responses, or configuration data.

Frequently asked questions

Does this tool send my JSON anywhere?
No. All parsing, formatting, and validation happens in your browser using the built-in JSON.parse / JSON.stringify. Nothing is sent to a server.
What does "Sort keys" do?
It reorders object keys alphabetically at every level. This is useful for producing stable diffs when comparing two JSON files.
Can I paste JSON with comments or trailing commas?
Not by default. The standard JSON specification does not allow them, so they will be reported as parse errors. Strip them out first, or convert from JSONC manually.
Is there a size limit?
The tool can handle multi-megabyte documents, but the browser may become slow on very large inputs because everything is rendered in a single text area.