On Tuesday, December 15, 2020, Google announced that it is refocusing the Structured Data Testing Tool and migrating it to a new domain serving the schema.org community by April 2021. The main purpose of the tool will be to check syntax and compliance of markup with schema.org standards. However, going forward, the tool will no longer check for Google Search rich result types.
The announcement comes after Google announced in July that the Rich Results Test is out of beta. In that blog post, Google said that the Structured Data Testing Tool would be deprecated. Since then, Google has received feedback from users and has decided to update the future of the tool.
To test your markup for Google Search rich result types, you can continue to use the Rich Results Test.
As an example, if you are trying to implement schema.org markup for rich event experiences on Google Search, based on our documentation, the Rich Results Test and Search Console are the best tools to make sure your markup is valid for Google Search. However, if you only want to make sure that you're using valid schema.org properties, or validate a type that we don't explicitly consume at this time (for example, ExercisePlan), then you will be able to use the refocused schema.org validator.
Update (August 9, 2021): The Schema Markup Validator has stabilized and is now available. Google has also redirected the Structured Data Testing Tool to a landing page, which will help users select the right tool for their needs.
The Schema Markup Validator is a tool that allows you to check if your structured data is properly formatted. This is important because incorrect formatting can prevent your data from being properly indexed by search engines.
The Structured Data Testing Tool is another tool that can be used to test structured data. This tool was previously used to test Schema.org markup, but it has since been deprecated in favor of the Schema Markup Validator.