Can I format JSON without changing data?

Yes—the formatter only changes whitespace and indentation, preserving the underlying data structure completely.

What happens if my JSON is invalid?

The tool highlights the syntax error with the exact error message and position so you can fix the issue quickly.

How do I use this with ChatGPT or Claude?

Ask: "Validate this JSON for me: [paste]" or link them to this tool. AI models can read error diagnostics and suggest fixes.

Can I minify JSON here?

This validator focuses on formatting and validation. For minification, use the formatter output and manually remove spaces or use developer tools.

What JSON features does this support?

This tool supports standard JSON (RFC 7159), including strings, numbers, booleans, null, arrays, and objects. Comments are not valid JSON and will cause validation to fail.

Can I validate nested or complex JSON?

Yes, this tool handles any valid JSON regardless of depth or complexity. Deeply nested objects, arrays, and mixed types all work.

Is there a file size limit?

No strict limit, but very large files (>10MB) may slow down the browser. For massive files, consider using command-line tools like `jq` instead.

My JSON has comments—why does it fail?

JSON specification does not support comments. Remove all // and /* */ comments before validating. If you need comments, use JSONC or YAML instead.

JSON

JSON Validator

Revision: April 15, 2026 • Validate and format JSON in your browser

Validate JSON instantly

Paste JSON data and the tool checks syntax, highlights errors, and formats the data with clean indentation. This is ideal for debugging API responses, config files, or developer data exchanges.

Enter JSON

Result

🔒 Why This Tool Works in Your Browser

JSON Validator operates entirely in your browser, analyzing and validating JSON structures locally without transmitting your data to external services. Your API responses, configuration files, and data structures remain completely private during validation—nothing is sent to servers, logged in analytics platforms, or tracked by third parties. This browser-based approach is essential for developers debugging API integrations, managing configuration systems, and working with sensitive data structures. The tool provides instant error detection, highlighting syntax issues, formatting problems, and structural violations against JSON standards. Whether you're troubleshooting REST API responses, validating configuration files, debugging data structures, or testing data pipelines, you get immediate feedback without network delays or external service dependencies. For development teams handling sensitive APIs—authentication tokens, user data, financial information—this local validation is critical. Your API responses containing confidential information never become visible to external validation services, analytics platforms, or third-party processors. You maintain complete sovereignty over your debugging process and development workflows. The browser-based transparency means you can inspect the validation logic, understand error messages precisely, and validate the tool's reliability independently. Whether you're building microservices, integrating multiple APIs, or managing complex data pipelines, local JSON validation lets you develop with confidence knowing your data structures and API communications remain completely confidential.