JSON Formatter

Beautify, minify, validate, repair & explore JSON — with a collapsible tree viewer and syntax highlighting.

Input JSON0 chars

Output

Formatted JSON will appear here…

How to Use the JSON Formatter

Paste your JSON into the input box, or drop / upload a .json file.
Pick your indentation (2, 3, 4 spaces or tab) and optionally tick Sort keys A–Z.
Choose an action — Beautify to pretty-print, Minify to compress, Validate to check syntax, or Repair to auto-fix common mistakes.
Switch to Tree view to explore nested data with collapsible nodes, or stay in Text view for syntax-highlighted output.
Copy or download the result, and read the stats bar for size, depth and key counts.

What Is JSON?

JSON (JavaScript Object Notation) is a lightweight, human-readable data format used to exchange information between systems. It's the most common format for web APIs, configuration files and data storage, using key-value pairs, arrays and nested objects to represent structured data in a clear, language-independent way.

This tool covers the full JSON workflow: Beautify turns messy or compact JSON into properly indented, readable code; Minify strips whitespace to shrink it for production; Validate checks syntax and points to the exact error location; and Repair fixes common problems like single quotes, trailing commas and unquoted keys so a broken snippet becomes valid JSON.

Common Use Cases

🔍Debug API responsesPretty-print and explore REST or GraphQL payloads in the tree viewer.

⚙️Edit config filesFormat and validate package, settings and manifest files.

🔧Fix broken JSONRepair single quotes, trailing commas and comments in one click.

📦Shrink for productionMinify large payloads to cut bandwidth and file size.

🧪QA & testingVerify API output matches the expected structure and types.

🎓Learn JSONSee clean, highlighted examples and understand nesting visually.

Why Choose Our JSON Formatter

🌳 Tree viewerCollapse and expand nested objects and arrays for fast exploration.
🎨 Syntax highlightingColor-coded keys, strings, numbers, booleans and nulls.
🔧 One-click repairAuto-fixes the most common JSON syntax mistakes.
📐 Precise errorsShows the exact line and column of any syntax problem.
📂 Drag & dropLoad files instantly, plus copy, download and sort keys.
🔒 100% privateEverything runs in your browser — no uploads, no tracking.

Common JSON Errors and Fixes

Missing comma — objects and arrays need commas between elements.
Trailing comma — JSON does not allow a comma after the last element.
Single quotes — JSON requires double quotes around keys and string values.
Unquoted keys — every object key must be wrapped in double quotes.
Comments — standard JSON does not support // or /* */.
Undefined values — JSON has no undefined; use null instead.

The Repair button attempts to fix all of these automatically, then re-validates the result.

Frequently Asked Questions

Is my JSON data safe?

Yes. All formatting, validation and repair happen entirely in your browser using JavaScript. Your data is never uploaded, stored or transmitted to any server.

What's the difference between formatted and minified JSON?

Formatted (beautified) JSON is indented and easy for humans to read. Minified JSON has all whitespace removed for the smallest possible size — ideal for production, APIs and data transfer.

What does the Repair button do?

It applies common fixes — converting single quotes to double quotes, removing trailing commas and comments, quoting unquoted keys, and replacing Python-style None/True/False — then re-validates. It's heuristic, so always review the result for important data.

Can I format very large JSON files?

Yes. The formatter handles large files efficiently, though performance depends on your device's memory. Very large files (over ~10 MB) may take a few seconds, and the tree view is best kept collapsed for huge structures.

How does the error location work?

When JSON is invalid, the tool reports the parser's message plus the exact line and column, and shows the surrounding snippet so you can jump straight to the problem.

Does it support JSON5 or JSONC?

The validator follows the strict JSON standard (RFC 8259). JSON5/JSONC features like comments, unquoted keys and trailing commas aren't valid — but the Repair button can often convert such snippets into strict JSON.

What do Escape and Unescape do?

Escape converts your JSON into a quoted, escaped string you can embed inside another string or code file. Unescape reverses that — turning an escaped string back into raw JSON.