JSON Formatter
Format and beautify your JSON instantly. Syntax validation, customizable indentation, minification. Free tool for developers.
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JSON Formatter: Beautify and Validate Your JSON Instantly
The JSON Formatter is a free online tool designed for developers who work with JSON data daily. Whether you're debugging an API response, preparing a configuration file, or analyzing logs, this tool allows you to format, validate, minify, and beautify your JSON in seconds, right in your browser.
JSON (JavaScript Object Notation) has become the most widely used data format for web exchanges, configurations, and REST APIs. Unfortunately, "raw" JSON is often compacted on a single line to save bandwidth, making it unreadable to the human eye. Our formatter solves this problem by automatically adding indentation, detecting syntax errors, and offering sorting and minification options.
💡 Why Does This JSON Formatter Exist?
Real-world scenario: A backend developer receives a 400 error on their API. The response contains 2000 characters of JSON on a single line. It's impossible to find the error visually. With our formatter, they paste the JSON, click "Format", and immediately identify that a comma is missing after the 15th field.
Many tools (terminals, logs, cURL responses) display unformatted JSON. Code editors can format JSON, but require creating a temporary file. Our tool provides an instant online solution, with no installation needed and real-time validation.
Beyond formatting, this tool validates JSON syntax and precisely reports errors (missing comma, unclosed quote, invalid character). It also offers minification to reduce payload size in production, and key sorting to easily compare two JSON structures.
How to Use
- Paste your raw JSON in the left text area
- Formatting is applied automatically in real-time
- Choose the indentation level (2 or 4 spaces) according to your preferences
- Enable "Sort Keys" to order properties alphabetically
- Click "Minify" to compress the JSON into a single line
- Use the copy button to retrieve the formatted result
🔧 Practical Use Cases
🐛 Debug API Responses
When testing an API with cURL or Postman, JSON responses are often compacted. Format them instantly to quickly identify missing fields or incorrect values.
⚙️ Prepare Configuration Files
JSON configuration files (package.json, tsconfig.json, .vscode/settings.json) need to be readable. Format them with consistent indentation before committing.
📊 Analyze JSON Logs
Many applications (Docker, Kubernetes, AWS CloudWatch) generate logs in JSON format. Format them to quickly extract important information (errors, timestamps, traces).
🔍 Validate Before Deployment
Before deploying a JSON configuration file to production (AWS Lambda, Cloud Functions, Terraform), validate its syntax to avoid parsing errors that would cause a startup crash.
📦 Minify for Production
Reduce the size of your static JSON files (i18n translations, config data) by removing spaces and line breaks. Achieve 20-40% file size reduction.
🔄 Compare JSON Structures
Use the "Sort Keys" option to compare two JSON objects with keys in different order. This makes Git diffs easier and helps detect structural changes.
✨ Why Use This Formatter Over Others?
100% Client-Side
No data is sent to any server. Your JSON stays private and secure in your browser.
Real-Time Validation
Syntax errors are detected instantly with precise indication of the problematic line and character.
Advanced Options
Customizable indentation (2 or 4 spaces), key sorting, minification, and one-click copy.
Mobile-Friendly
Responsive interface that works on all devices, from smartphone to desktop.
Ultra-Fast
No page loading, no ads, no account required. Just paste → format → copy.
Free & Unlimited
No restriction on JSON file size (up to 10 MB) or number of uses.
❓ Frequently Asked Questions (FAQ)
What's the difference between formatting and minifying JSON?
Formatting (or "beautifying") adds indentation, line breaks, and spaces to make JSON readable by humans. Useful for debugging and code review.
Minifying does the opposite: removes all spaces, line breaks, and indentation to reduce file size. Useful in production to save bandwidth and speed up load times (20-40% size reduction).
Is my JSON data sent to a server?
No, absolutely not. This tool runs entirely client-side (in your browser). Formatting, validation, and minification happen locally using JavaScript.
You can even use this tool offline (after the first visit) as it's available as a PWA (Progressive Web App). Your sensitive data (tokens, passwords, API keys) stays private.
What are the most common JSON errors detected by the validator?
The most common errors:
- Trailing comma:
{"\"key\": \"value\",}"}is invalid in JSON (but valid in JavaScript) - Single quotes: JSON requires double quotes
"key", not'key' - Unquoted keys:
{key: \"value\"}is invalid, must be{"\"key\": \"value\"}"} - Comments: JSON doesn't support comments
// commentor/* comment */ - Unescaped characters: Line breaks must be
\n, quotes\"
Should I use 2 or 4 spaces for indentation?
It's a matter of personal preference and team convention:
- 2 spaces: More compact, standard for modern JavaScript/TypeScript projects (ESLint, Prettier)
- 4 spaces: More readable for some developers, standard in many Python and Java projects
The important thing is consistency within a project. Configure your linter (ESLint, Prettier) to enforce the same style everywhere.
How does the tool handle Unicode characters and emojis?
The tool perfectly preserves all Unicode characters, including emojis, accented characters, Chinese characters, Arabic, etc.
Valid example: {"\"name\": \"Alice 🚀\", \"city\": \"Montreal\"}"}
Some formatters escape Unicode characters as \uXXXX, making JSON less readable. Our tool preserves original characters by default for better readability.
Can I use this tool in command line or scripts?
This tool is designed for browser use. To format JSON in command line, use:
- jq:
echo '{\"a\":1}' | jq .(Unix/Linux/Mac) - Python:
echo '{\"a\":1}' | python -m json.tool - Node.js:
node -e "console.log(JSON.stringify(JSON.parse(process.argv[1]), null, 2))" '{\"a\":1}'
For CI/CD integration, prefer Prettier with prettier --parser json.
What is the "Sort Keys" option for?
Alphabetical key sorting allows you to easily compare two JSON structures with properties in different order.
Example: These two JSONs are identical but with keys in different order:
After sorting, both will be identical, making Git diffs easier and detecting real changes.
⚠️ Warning: Key order may be important in some contexts (display order, legacy systems). Only use sorting if order has no semantic importance.
📚 Best Practices
Always validate before committing
Use Git hooks (pre-commit) with Prettier or ESLint to automatically format JSON files before each commit.
Adopt a consistent indentation convention
Choose 2 or 4 spaces and stick with it throughout the project. Document this convention in an .editorconfig or .prettierrc file.
Never include comments in pure JSON
JSON doesn't support comments. If you need documentation, use JSON5, JSONC (JSON with Comments), or separate documentation files.
Never store secrets in plain text in JSON files
Passwords, API tokens, and private keys should be in environment variables or secret managers (Vault, AWS Secrets Manager), not in versioned JSON files.
Only minify in production
Keep your source JSON files formatted for easier maintenance. Minify automatically during the production build (Webpack, Vite, etc.).