FlowToolkit
Dev

JSON Formatter

Beautify, minify, and validate JSON instantly.

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About this tool

Paste raw JSON and format it with proper indentation, or minify it to one line. Errors are reported with line and column. Runs entirely in your browser.

JSON formatting at a glance

JavaScript Object Notation has become the universal language of APIs, configuration files, and inter-service communication. It is easy for machines to parse and reasonably readable by humans — but only when it is well-indented. A minified payload returned by a REST API or written to a log file is a wall of text, and a single missing comma or unbalanced bracket can take minutes to find by eye.

A formatter solves that. Paste raw JSON and the tool re-emits it with consistent indentation, sorted bracket alignment, and a structure that makes nesting obvious. Errors are highlighted with the exact line and column number so you can spot the problem at a glance.

Features

  • Beautify mode with configurable indentation: two spaces, four spaces, or tab characters.
  • Minify mode that strips all whitespace for production payloads.
  • Strict validation against the JSON specification with line and column error reporting.
  • Copy-to-clipboard and download buttons for the formatted result.
  • Works on any modern browser — desktop or mobile.

Common use cases

Developers reach for a JSON formatter dozens of times a day: inspecting an API response, debugging a webhook payload, prettifying a configuration file before checking it into version control, comparing two JSON documents side by side, or pasting a JWT body to read the claims. Marketers and analysts use it to inspect product feeds, Schema.org markup, and structured data returned by SEO tools.

Because the parser runs locally via the browser native JSON.parse, the tool handles JSON of any practical size — from a one-line API response to a multi-megabyte data dump — without ever transmitting it to a server.

Frequently asked questions

Does it send my JSON to a server?

No. Parsing happens via the browser native JSON.parse function. The JSON never leaves your device.

What indentation is used?

Two spaces by default. You can switch to four spaces or tab to match your project conventions.

How do I beautify JSON?

Paste raw JSON into the input area and the formatted output appears instantly. Use the copy button to grab it.

How do I minify JSON?

Click Minify and the JSON is collapsed to a single line with all unnecessary whitespace removed — useful for production payloads.

What happens if my JSON is invalid?

The error message shows the exact line and column where parsing failed, with a hint about the likely cause (missing comma, unbalanced bracket, trailing comma, unquoted key).

Can it handle very large JSON files?

Yes. The parser scales to multi-megabyte payloads. Performance depends on your device but a typical laptop handles 50 MB JSON files comfortably.

Does it support JSONC or JSON5?

No. The formatter follows the strict JSON specification: no comments, no trailing commas, no unquoted keys. Convert JSONC or JSON5 to standard JSON first.

Can I validate JSON without formatting it?

Yes. If the input parses, it is valid. The error message field is empty for valid JSON and populated with line/column info for invalid JSON.