About

Developer Tools Online (validatethis.org) offers free, fast validation for JSON, HTML, robots.txt, and Schema.org structured data.

The tools are designed for developers, CI/CD pipelines, and AI coding assistants. No signup is required for basic use; an API is available for integration.

Tools

• JSON Validator
• HTML Validator
• robots.txt Tester
• Schema.org Validator

For API documentation, see API Documentation. For support or feedback, Contact.