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About JSONLint.app

JSONLint.app is a free, fast JSON validator and formatter built for developers. It provides 40+ tools for working with JSON — from validation and formatting to conversion, diffing, schema validation, and code generation.

Why JSONLint.app?

JSON is everywhere — APIs, configuration files, data storage, and more. Yet debugging JSON errors can be frustrating. A single missing quote or trailing comma can break an entire application, and the error messages from parsers are often cryptic.

JSONLint.app aims to be the most helpful JSON tool on the web. Beyond basic validation, we offer:

  • Clear, actionable error messages with line numbers
  • Automatic formatting and beautification
  • Conversion tools for CSV, XML, YAML, Excel, and SQL
  • Code generators for TypeScript, Python, Java, Go, and more
  • Schema validation and generation
  • Diff comparison and path queries

Privacy First

Every tool runs entirely in your browser. The JSON, code, and files you paste or upload are processed client-side and are never transmitted to or stored on our servers — your data never leaves your machine, and there are no accounts to create.

To keep the site free, we use privacy-respecting analytics (to understand which tools people use) and advertising. These never have access to the content you process. You can read exactly what is and isn't collected in our Privacy Policy.

Powered by Modern Tools

JSONLint.app uses Shiki for syntax highlighting — the same TextMate grammar engine that powers VS Code. This gives you accurate, beautiful code highlighting whether you're editing JSON in our validator or reading code examples in our documentation.

Free for Everyone

JSONLint.app is free to use, with no sign-up and no limits. We believe in giving back to the developer community with fast, high-quality tools that respect your privacy.

Get in Touch

Have feedback, suggestions, or found a bug? We'd love to hear from you. Email us at jsonlintapp@gmail.com or visit our Contact page. You can also review our Privacy Policy and Terms of Service.

Thanks for using JSONLint.app. Happy coding!