JSON Formatter

Format, validate, and beautify JSON online with readable indentation, syntax checking, and copy-ready output for APIs, logs, and config files.

Indent:

Input

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Output

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What is JSON Formatter

Last reviewed: April 18, 2026

JSON (JavaScript Object Notation) is a lightweight, human-readable data format used almost everywhere on the web for APIs, config files, and log output.

JSON Formatter is an online tool that takes raw or minified JSON and turns it into clean, readable output with consistent indentation and line breaks.

It helps developers validate JSON structure, spot syntax mistakes faster, and prepare payloads for APIs, configs, logs, and debugging without leaving the browser.

Why use it

Make nested objects and arrays easier to read during debugging.
Validate JSON before sending it to an API, app, or database workflow.
Pretty print minified JSON from logs, responses, or config files.
Standardize indentation before sharing JSON with teammates.
Catch common syntax issues such as trailing commas or missing quotes.

Features

Pretty print with 2-space, 4-space, or tab indentation
Client-side validation that pinpoints the failing position
Expands minified JSON from API responses and log lines
Copy or download the formatted output
Runs entirely in the browser — JSON never leaves your device

How to use JSON Formatter

Paste your JSON. Paste raw or minified JSON into the input panel. You can drop in API responses, log entries, or config snippets.
Choose an indentation style. Pick 2 spaces, 4 spaces, or tabs to match your project's formatting conventions.
Copy the formatted JSON. Copy the pretty-printed output back into your editor, ticket, or pull request, or download it as a .json file.

Example (before/after)

Before formatting

{"user":{"id":12,"name":"Ada","roles":["admin","editor"]},"active":true,"settings":{"theme":"dark","alerts":false}}

After formatting

{
  "user": {
    "id": 12,
    "name": "Ada",
    "roles": [
      "admin",
      "editor"
    ]
  },
  "active": true,
  "settings": {
    "theme": "dark",
    "alerts": false
  }
}

Common errors

Trailing commas

Standard JSON does not allow a comma after the last property or array item.

Fix: Remove the final comma before closing braces or brackets.

Unquoted property names

JSON keys must use double quotes, even if JavaScript object syntax allows bare identifiers.

Fix: Wrap every property name in double quotes.

Single quotes instead of double quotes

JSON strings must use double quotes for keys and values.

Fix: Replace single quotes with double quotes where needed.

Missing or mismatched braces

Nested objects and arrays often break when a closing bracket or brace is missing.

Fix: Check the structure from the error line and balance every opening token.

FAQ

What does a JSON Formatter do?

A JSON Formatter pretty prints JSON by adding indentation and line breaks so the structure is easier to read, review, and debug.

Does this JSON Formatter validate JSON too?

Yes. If the input is invalid JSON, the formatter reports an error instead of producing misleading output.

Is my JSON sent to a server?

The formatter runs in the browser for normal formatting, so pasted JSON stays on your device while you work.

Can I format minified JSON from an API response?

Yes. Paste minified JSON into the input panel and the tool will expand it into readable, indented output.

What indentation options are available?

The tool supports 2 spaces, 4 spaces, and tab indentation so you can match your preferred coding style.

How is this different from JSON5 or JSONL?

Standard JSON is what this formatter expects. JSON5 adds comments, trailing commas, and unquoted keys; JSONL stores one JSON object per line. Use the dedicated JSON5 or JSONL tools for those variants.

Why is my JSON invalid even though it looks fine?

Common culprits are trailing commas, single quotes around keys or strings, comments, and unescaped control characters. The error message points to the first position where parsing failed so you can fix the structure there.

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