JSON Formatter
Format, validate, and prettify JSON with syntax highlighting and error detection
Introduction
JSON (JavaScript Object Notation) is everywhere in modern software development—it's the standard format for API responses, configuration files, data storage, and communication between web services. However, JSON data is often transmitted in minified format, compressed into a single line with all whitespace removed to reduce file size and bandwidth usage. While this compression is great for machines, it makes JSON completely unreadable for humans who need to debug API responses, understand data structures, or edit configuration files. Our JSON Formatter tool provides instant beautification and validation of JSON data, transforming minified or messy JSON into properly indented, human-readable format with syntax highlighting. The formatter supports both prettification and minification, with customizable indent sizes to match your project's coding standards. Real-time syntax validation catches errors immediately and provides precise line and column numbers.
Who Should Use This Tool?
- Backend developers debugging API responses and validating JSON data structures
- Frontend engineers formatting API responses to understand data structures before building UI
- DevOps professionals managing configuration files for applications and infrastructure
- Technical writers creating formatted JSON examples for API documentation
- QA engineers inspecting API responses during testing to verify data structures
- Data scientists exploring JSON data extracted from APIs and databases
- System administrators editing and validating JSON configuration files
- Full-stack developers working with JSON across the entire stack
- API designers creating and documenting JSON schemas and example responses
How This Tool Works
The JSON Formatter parses your input text using JavaScript's built-in JSON.parse() function, which validates syntax and constructs an in-memory object representation. If parsing succeeds, the tool uses JSON.stringify() with spacing parameters to generate formatted output with proper indentation and line breaks. For prettification, the spacing parameter adds the selected number of spaces (2, 4, 6, or 8) for each nesting level. For minification, spacing is set to zero, removing all unnecessary whitespace. Syntax highlighting applies color coding to different JSON elements (keys, strings, numbers, booleans, null values) using pattern matching. If parsing fails, the tool catches the error and displays the exact line and column number where the syntax problem occurred. All processing happens in your browser with no server communication.
Try JSON Formatter Now
Use the interactive tool below to get instant results
Client-Side Processing
Your JSON is processed entirely in your browser. No data is sent to any server.
Options
Input JSON
💡 Quick Tips
- • Prettify: Formats JSON with proper indentation for readability
- • Minify: Removes all whitespace to reduce file size
- • Indent Size: Choose 2, 4, 6, or 8 spaces for formatted output
- • Validation: Automatically detects syntax errors with line numbers
- • Copy: Click the copy button to copy formatted JSON to clipboard
⚠️ Common JSON Errors
- • Missing quotes around property names (use "key" not key)
- • Single quotes instead of double quotes (use " not ')
- • Trailing commas after last item in arrays or objects
- • Unescaped special characters in strings (\n, \t, \", \\)
- • Using undefined instead of null
How to Use Json Formatter
Paste Your JSON Data
Copy whatever JSON you have and paste it into the input box. API response, config file, database dump, code snippet—anything works. Click Load Sample if you want to see how formatting looks before using your own data.
Select Format Mode
Hit Prettify to add line breaks and indentation so humans can actually read it. Or pick Minify to squash everything into one line for smaller file sizes. When prettifying, choose indent size (2, 4, 6, or 8 spaces) based on what looks good to you or whatever your project uses.
Format and Validate
Click the format button. The tool checks syntax instantly and either shows your formatted JSON or spits out an error message with the exact line and column number where something is wrong. Catches stuff like trailing commas, single quotes instead of double, or missing brackets.
Copy the Formatted Result
Check out the color-coded output—keys, values, strings, numbers all color-coded so you can scan it easily. See character count and line count stats if you care about file size. Hit Copy to grab the formatted JSON and paste it wherever you need it.
Use Cases for Json Formatter
API Response Debugging
APIs often return minified JSON that is basically unreadable. Format it with indentation so you can actually see the structure, find the fields you need, and figure out why your integration is not working. Way easier than squinting at one long string.
Documentation and Examples
If you are writing docs, README files, blog posts, or tutorials, prettified JSON examples with proper indentation are so much easier for readers to understand and copy. Nobody wants to parse minified JSON in a tutorial.
Configuration File Management
Config files are way easier to edit and maintain when they have proper indentation. You can see nested structures clearly, spot missing commas, and avoid errors when you or teammates make changes later.
Data Compression and Transmission
Minify JSON before sending it over the network to save bandwidth. Removing whitespace can shrink file sizes noticeably, which matters if you are sending lots of API requests or have mobile users on slow connections.
JSON Syntax Validation
Paste JSON to check if the syntax is valid before deploying or using it. The tool catches errors immediately and tells you exactly where the problem is—saves you from debugging runtime errors in production.
Key Features
100% Private and Secure
Processing happens entirely in your browser. Your JSON never leaves your device. Safe for API keys, secrets, or any sensitive data.
Customizable Indentation
Pick 2, 4, 6, or 8 spaces. Match your project standards or just whatever looks readable to you.
Real-Time Syntax Validation
Catches syntax errors instantly with exact line and column numbers. No guessing where the problem is.
Syntax Highlighting
Color-coded keys, strings, numbers, booleans, nulls. Makes complex JSON way easier to scan.
Statistics and Metrics
Shows character count and line count for original and formatted JSON. Useful if you care about file size changes.
No Software or Registration
Works in any browser. No downloads, no accounts, no setup. Just open and use.
Frequently Asked Questions
Does this tool upload my JSON data to a server?
Nope. Everything happens in your browser using JavaScript. Your data never leaves your device, nothing gets uploaded anywhere. Safe for formatting API responses with tokens, config files with secrets, or anything else you do not want leaving your computer.
What is the difference between prettify and minify?
Prettify adds whitespace and indentation so humans can read it easily—good for debugging, docs, and config files. Minify strips all whitespace to make the smallest file possible—good for reducing bandwidth when sending JSON over the network. Same data, different formatting.
How do I fix JSON syntax errors reported by the tool?
The tool tells you exactly which line and column has the problem. Common fixes: put property names in double quotes (not single), remove trailing commas after the last item in arrays or objects, use double quotes for strings, and make sure all brackets and braces are closed properly.
What indent size should I use when prettifying JSON?
2 spaces is pretty common in JavaScript and web dev projects—compact but readable. 4 spaces is traditional and easier on the eyes for deeply nested stuff. Pick whatever your project uses or whatever looks good to you. Functionality is the same either way.
Can this tool handle large JSON files?
Moderately large files (a few megabytes) work fine. Huge files over 10-20MB might slow down your browser or crash the tab because everything runs in browser memory. For massive JSON files, use command-line tools like jq or Python scripts instead.