> For the complete documentation index, see [llms.txt](https://docs.appstrategy.com/apprules-r-documentation/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.appstrategy.com/apprules-r-documentation/platform-products/apprules-data-migration-engine/validations-error-handling-and-notifications.md).

# Validations, Error Handling & Notifications

Validations, error handling, and notifications are critical components for executing successful data migration, data replication and data synchronization projects. 

appRules includes the following options for error handling and notifications:

* Automatic and on-demand validation is available for all workflow activities.         ![](/files/zhDrE2a6IsvbT7qUWFNT)    
* Automatic and on-demand validation is available for all target entity definitions.
* Incomplete, Terminated, and errored job instances can be **rerun** to process only the incomplete or errored records.  This saves a great deal of time as successfully transferred records are skipped - greatly reducing the load trips to the source.                                                     ![](/files/IKnLI9aBgkoPBD7XwNHt)
* Edit the LoaderSettings property of any Target Entity definition to optionally configure error tolerance threshold and the action to perform when the error limit is exceeded: ![](/files/I6FVdgiaLCzES5ZGskN2)
* Edit the Notifications tab of the Project Settings to define project-wide notifications:![](/files/bjimBktxnzHzyuySM7FW)


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