JSONLint.app

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

All tools run entirely in your browser — your data never leaves your machine. No accounts, no tracking, no data collection.

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.

Open Source

This project is based on an open-source project licensed under the MIT License. We believe in giving back to the developer community with free, high-quality tools.

Get in Touch

Have feedback, suggestions, or found a bug? We'd love to hear from you. Open an issue or contribute on GitHub.

Thanks for using JSONLint.app. Happy coding!