JSON Formatter

Validate, format, minify, analyze, and inspect JSON as a tree locally.

Formatter settings

Mode

Input

Private by design: your data never leaves your device.

, drop a file, or to begin.

Output

Paste valid JSON to see the preview.

Paste valid JSON to see the preview.

Good to know

The JSON Formatter formats, minifies, and analyzes JSON directly in your browser. It is especially useful when API responses, configuration files, webhook payloads, or log output need to become readable quickly. Instead of checking dense JSON blocks manually, the tool shows syntax errors, duplicate keys, and structured output immediately.

Valid JSON consists of objects, arrays, strings, numbers, booleans, and null. A missing comma, an extra quote, or a disallowed comment can be enough for an API or application to reject a payload. The formatter helps validate, beautify, minify, and inspect JSON data without sending content to a server.

Typical use cases

Debug API responses

Format compact JSON responses from REST APIs, webhooks, or browser developer tools to understand fields, arrays, and nested objects faster.

Prepare JSON for reviews

Use pretty print, indentation, and optionally sorted keys so JSON configuration can be reviewed more easily in pull requests and documentation.

Inspect production data locally

Inspect sensitive sample payloads, log fragments, or internal configuration locally in the browser without uploading them to external JSON online services.

Tips for better results

Read the error message first

When JSON is invalid, the issue is often just before the reported position: a missing comma, wrong quotes, trailing comma, or a comment.

Use minify mainly for delivery

Minified JSON saves space but is harder to read. For debugging and code review, formatted JSON with stable indentation is usually better.

How it works

Video

Step by step

  1. 1

    Choose a mode

    Choose a mode

    Choose between pretty print for readable JSON and minify for the smallest possible file size.

  2. 2

    Paste your JSON

    Paste your JSON

    Paste JSON text, drop a file via drag and drop, or choose one via “browse”.

  3. 3

    Review the result

    Review the result

    View the result as formatted text or as an interactive tree; adjust advanced settings if needed.

  4. 4

    Copy or download

    Copy or download

    Copy the result to the clipboard or download it as a .json file.

Features

Pretty print and minify

Format JSON with readable indentation, or minify it down to the smallest possible size.

Live validation with precise error messages

Syntax errors and duplicate keys are detected as you type, with a clear, specific error message.

Interactive tree view

Alongside the formatted text view, the same structure can be explored as a navigable tree with object and array summaries.

Configurable formatting

Indentation (2, 3, 4 spaces or tab), line endings (LF/CRLF), key sorting, and non-ASCII escaping can each be configured individually.

Up to 50 MB, no upload

JSON files up to 50 MB are processed entirely in your browser. There is no server round trip.

Copy or download the result

The formatted or minified result can be copied to the clipboard or downloaded as a file with one click.

Frequently asked questions

Is the JSON Formatter free?

Yes. The JSON Formatter is completely free to use, with no sign-up and no usage limit.

Are my JSON files uploaded anywhere?

No. All processing happens locally in your browser. Pasted text and selected files are never sent to a server.

How large can the JSON file be?

Up to 50 MB per file.

What is the difference between pretty print and minify?

Pretty print adds indentation and line breaks for readability. Minify removes all non-essential whitespace to make the file as small as possible.

Does the tool detect duplicate keys or invalid JSON?

Yes. For duplicate keys and syntax errors, the tool shows a precise error message instead of silently changing the result.

Can I see a tree structure instead of the formatted view?

Yes. The “Tree” tab in the output shows the same structure as a navigable tree with object and array summaries.

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