If you’re using Grails for a frontend without direct database access, there are four things you need to do.

1. Remove Grails’ Hibernate plugin.

   grails uninstall-plugin hibernate

2. Delete the datasource configuration file conf/DataSource.groovy
3. Explicitly declare services as non-transactional. The default is true and your class methods would be proxied, but without the Hibernate plugin there is no transaction manager and the deployment will fail.

   class SomeService {
   	static transactional = false
   	// ...
   }

4. Use command objects instead of domain objects, particularly if you need validation.