Google has updated the structured data testing tool page to a page that instructs the user to either go to the rich results testing tool on Google or the schema markup validator on Schema.org.
Google announced this change over here saying "the Schema Markup Validator has stabilized, and Google now redirects the Structured Data Testing Tool to a landing page to help you select the right tool."
Here is a screenshot of this page:
It says Google recommends that you start with the Rich Results Test to see what Google rich results can be generated for your page. For generic schema validation, use the Schema Markup Validator to test all types of schema.org markup, without Google-specific validation.
Rich Results Test: The official Google tool for testing your structured data to see which Google rich results can be generated by the structured data on your page. You can also preview how rich results can look in Google Search.
Schema Markup Validator: Validate all Schema.org-based structured data that's embedded in web pages, without Google feature specific warnings.
Google has been telling us this tool will be going away for a long time and it did. The Schema.org validator went live a couple months back.
The time has come. Google has officially shut down the Structured Data Testing Tool.
— Brodie Clark (@brodieseo) August 10, 2021
When trying to access: https://t.co/9LLJyFIqMi, you're now redirected to choose from the RRT or Schema Markup Validator.
But don't worry – Schema Markup Validator is very similar to the SDTT! pic.twitter.com/bIkIfeMD4v
Forum discussion at Twitter.
