@wkgcls DQX requires a Databricks platform license for production use, and its licensing restricts usage to environments connected with Databricks Services. This means you cannot use DQX freely in external Spark environments such as AWS EMR

To your questions

1. Yes, DQX requires a Databricks platform agreement for legitimate usage.

2.No, there are currently no publicly documented licensing options that allow Databricks Labs projects, including DQX, to be used outside the Databricks platform.

3.Yes, there are several open-source and permissively licensed alternatives example-  Great Expectations: Python-based framework with Spark DataFrame support, configurable validation rules, and strong community adoption.