Format, validate, and beautify JSON data instantly. Perfect for API testing, web development, and debugging. Free, browser-based, no signup.
A JSON formatter (also called a JSON beautifier or JSON pretty-printer) takes raw, minified, or poorly indented JSON text and reformats it with consistent indentation, line breaks, and spacing — making it easy to read and understand. JSON (JavaScript Object Notation) is the universal data format used in APIs, configuration files, databases, and web applications. When you receive a raw API response or export data from a database, it's often compressed into a single unreadable line. Our formatter instantly transforms it into cleanly structured, human-readable JSON with syntax highlighting.
Our formatter uses JavaScript's native JSON.parse() to validate your input and detect any syntax errors, then JSON.stringify() with configurable indentation to produce clean, properly formatted output. Validation runs on every keystroke so you get immediate feedback. All processing happens in your browser — your JSON data is never sent to a server, which is important when working with API keys, tokens, or sensitive configuration values.
Paste your JSON
Copy your raw or minified JSON and paste it into the input area. You can also type JSON directly.
Instant validation
The tool validates your JSON in real time. Syntax errors are highlighted immediately with a description of what went wrong and where.
View formatted output
The formatted, indented JSON appears in the output panel with optional syntax highlighting for keys, strings, numbers, and booleans.
Copy or download
Click "Copy" to copy the formatted JSON to your clipboard, or "Download" to save it as a .json file.
🔌 API Debugging
Format API responses from Postman, curl, or browser dev tools.
⚙️ Config Files
Validate and format package.json, tsconfig.json, and other config files.
🗄️ Databases
Read and format JSON exports from MongoDB, PostgreSQL JSON columns.
📋 Logging
Format log entries and error reports containing JSON payloads.
📡 Webhooks
Inspect and understand incoming webhook payloads from third-party services.
🧪 Testing
Format expected/actual JSON values when writing unit or integration tests.
What is the difference between JSON formatting and validation?
Formatting makes JSON readable by adding indentation and line breaks. Validation checks whether the JSON is syntactically correct — our tool does both simultaneously.
Is my JSON data sent to a server?
No. All formatting and validation happens entirely in your browser using JavaScript. Your JSON data never leaves your device — important for sensitive API keys and config values.
What are common JSON syntax errors?
Common errors include: trailing commas (not allowed in standard JSON), single quotes instead of double quotes, unquoted keys, missing commas between properties, and unclosed brackets or braces.
Can I format very large JSON files?
Yes, the tool handles large JSON files well since processing is done by your browser's JavaScript engine. Files up to a few MB should format instantly.
What is the difference between JSON and JSON5?
JSON5 is an extension of JSON that allows comments, trailing commas, and single quotes. Standard JSON (used by our tool) does not allow these. Most APIs and tools use standard JSON.