Free JSON Validator - Parse, Format & Validate JSON Online
Validate and format your JSON data instantly with our free online JSON validator. Detect syntax errors, beautify JSON with proper indentation, and ensure your data is valid.
JSON Validator Tool
💡 Paste or type your JSON here. Auto-validates as you type.
No JSON to display
Enter JSON in the editor to see formatted output
📋 Read-only formatted preview. Use Copy button to copy.
🔒 100% Private & Secure
All validation happens in your browser. Your data never leaves your device and is never sent to any server.
What is JSON?
JSON (JavaScript Object Notation) is a lightweight data-interchange format that is easy for humans to read and write and easy for machines to parse and generate. It is based on a subset of JavaScript, but is language-independent and widely used across different programming languages.
JSON is built on two structures: objects (collections of name/value pairs) and arrays (ordered lists of values). These structures make JSON an ideal format for transmitting data between a server and web application, configuration files, and API responses.
How to Validate JSON
Validating JSON ensures that your data follows the correct syntax rules. Here's how to use our JSON validator:
- Paste your JSON: Copy and paste your JSON data into the editor above
- Automatic validation: The validator will automatically check your JSON syntax
- Review results: If valid, you'll see a success message. If invalid, you'll get detailed error information
- Format (optional): Use the format button to beautify your JSON with proper indentation
- Copy result: Copy the validated and formatted JSON back to your application
Common JSON Errors and How to Fix Them
1. Missing Quotes Around Keys
Error: Keys must be enclosed in double quotes.
❌ Incorrect:
{name: "John"}✅ Correct:
{"name": "John"}2. Trailing Commas
Error: JSON does not allow trailing commas after the last item.
❌ Incorrect:
{"name": "John", "age": 30,}✅ Correct:
{"name": "John", "age": 30}3. Single Quotes Instead of Double Quotes
Error: JSON requires double quotes, not single quotes.
❌ Incorrect:
{'name': 'John'}✅ Correct:
{"name": "John"}4. Unescaped Special Characters
Error: Special characters in strings must be escaped.
❌ Incorrect:
{"message": "He said "Hello""}✅ Correct:
{"message": "He said \"Hello\""}Frequently Asked Questions
Is my JSON data secure?
Yes! All validation and formatting happens entirely in your browser. Your JSON data never leaves your device and is never sent to any server. This ensures complete privacy and security for your sensitive data.
Do I need to create an account?
No! Our JSON validator is completely free and requires no sign-up. Just paste your JSON and start validating immediately.
What is the maximum JSON size I can validate?
Since validation happens in your browser, the size limit depends on your device's memory and browser capabilities. Most modern browsers can handle JSON files several megabytes in size without issues.
Can I use this tool offline?
Once the page is loaded, the validator works entirely client-side, so you can continue using it even if your internet connection drops. However, you'll need an internet connection to initially load the page.
What browsers are supported?
Our JSON validator works on all modern browsers including Chrome, Firefox, Safari, Edge, and Opera. We recommend using the latest version of your browser for the best experience.