JSON Validator
Validate, format, and fix JSON errors instantly. 100% client-side processing — your data never leaves your browser.
How to Validate JSON
Paste Your JSON
Copy your JSON data and paste it into the input editor. The validator will automatically detect when you paste.
Click Validate
Click the Validate button to check your JSON. You'll instantly see if it's valid or get detailed error information.
Format or Copy
Once validated, format your JSON with custom indentation, view it as a tree, copy it, or download it as a file.
About JSON Validation
JSON (JavaScript Object Notation) is a lightweight data interchange format that's easy for humans to read and write, and easy for machines to parse and generate. It has become the standard format for APIs and configuration files in modern web development.
Our JSON validator helps you quickly identify syntax errors in your JSON data. Whether you're debugging an API response, writing configuration files, or working with data exports, this tool ensures your JSON is properly formatted before you use it.
Unlike other online validators, our tool processes everything locally in your browser. This means your sensitive data — whether it's API keys, user information, or proprietary business data — never gets transmitted to any server. Your privacy is guaranteed.
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Frequently Asked Questions
JSON validation is the process of checking whether a string conforms to the JSON (JavaScript Object Notation) data format specification. A valid JSON must have properly formatted syntax including correct use of braces, brackets, colons, commas, and properly quoted strings.
Common JSON syntax errors include: trailing commas after the last element, single quotes instead of double quotes, missing quotes around keys, unescaped special characters in strings, and comments (JSON doesn't support comments). Our validator will show you exactly where these errors occur.
No, absolutely not. All JSON processing happens entirely in your browser using JavaScript. Your data never leaves your device and is never transmitted to any server. This makes our tool completely safe for validating sensitive or confidential JSON data.
Our validator can handle JSON files up to 5MB without any issues. For very large files, processing may take a moment, but it all happens locally in your browser. There are no server-side limits since no data is uploaded.
Unexpected token errors usually mean there's a character where JSON doesn't expect it. Common fixes include: adding missing commas between elements, removing trailing commas, ensuring all strings use double quotes, and checking for unescaped characters. Our validator shows the exact line and column of the error.