Office utility

JSON Formatter — format, minify, and validate JSON

Paste JSON on the left, format or minify it, then copy or download the cleaned output. This runs locally in your browser (no uploads).

Indentation

Input JSON

Tip: if your JSON came from logs or an API, validate first to locate errors quickly.

Output

Ready.

Common uses

Clean JSON before analysis, convert to CSV, or share readable payloads in reports.

Validate JSON before converting with JSON to CSV.
Fix broken indentation and remove trailing commas introduced by copy/paste.
Minify payloads before submitting to APIs or storing in a database.

JSON Formatter: Validate, Format and Beautify JSON

Minified JSON from APIs, broken JSON from copy-paste errors, and unreadable single-line data are all common frustrations. This JSON formatter validates your JSON for syntax errors, beautifies it with proper indentation, and minifies it back when needed — entirely in your browser.

How to format JSON

Paste your JSON into the input area.

Click Format/Beautify — the output shows properly indented, readable JSON.

Or click Minify to compress it back into a single line for use in code or APIs.

Copy the output or download as a .json file.

Common use cases

API debugging — Paste a raw API response to read it clearly and spot unexpected fields.

Configuration file editing — Beautify minified config files for editing, then minify again before deployment.

Finding JSON syntax errors — The validator highlights exactly where a comma, bracket, or quote is missing.

Code review — Format JSON payloads in pull request comments for readability.

Common JSON errors and fixes

Trailing commas — JSON does not allow a comma after the last item in an array or object. Remove it.

Single quotes — JSON requires double quotes for all strings and keys. Replace all single quotes.

Unescaped special characters — Backslashes, newlines, and tabs inside strings must be escaped (\n, \t).

Missing quotes around keys — Unlike JavaScript objects, JSON requires all keys to be in double quotes.

Frequently asked questions

Does this tool fix errors automatically?

The formatter validates and flags errors but does not auto-correct them, because automated correction could change the meaning of your data. It tells you exactly where the error is so you can fix it intentionally.

Is there a size limit?

The tool handles large JSON files limited only by your browser's memory. Files up to 10 MB format reliably on any modern computer.

Is my JSON data private?

Yes — everything runs locally in your browser. API keys, tokens, and sensitive data in your JSON never leave your device.

Related tools

JSON syntax rules every developer should know

JSON is strictly defined — a single misplaced character makes an entire file invalid. The most common issues: strings must use double quotes (not single quotes); no trailing commas after the last item in an array or object; no comments (JSON5 supports comments, standard JSON does not); booleans and null are unquoted (true not "true"); and all keys must be quoted strings.

When to minify vs beautify

Minify when: sending JSON over a network in API requests (smaller payload = faster transfer), storing in databases or config files where human readability is not needed, embedding in HTML or JavaScript bundles.

Beautify when: debugging API responses, reviewing configuration files before editing, sharing JSON in documentation or code reviews. Beautifully indented JSON is far easier to read, audit, and modify correctly than a single-line blob.

JSON in real-world workflows

JSON is used in virtually every modern web application. REST APIs return JSON responses; web application configurations (package.json, tsconfig.json, .eslintrc) are written in JSON; cloud services like AWS Lambda, Netlify Functions, and Firebase use JSON for event payloads and configuration. Being able to quickly validate and format JSON is a core productivity skill for developers, data analysts, and anyone working with APIs or configuration systems.