# 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.         ![](https://1923141441-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F-MFjmFrZ8sef1J7qkr6H%2Fuploads%2FdleR0uT0JIQPls6GNwlv%2Fimage.png?alt=media\&token=349ed2dc-1acd-414f-ad67-f173d4c4163b)    
* 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.                                                     ![](https://1923141441-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F-MFjmFrZ8sef1J7qkr6H%2Fuploads%2FndvsWrkLrwxifi4g3Zmn%2Fimage.png?alt=media\&token=7c34d0e1-eb3e-4614-bf0f-28a38c714928)
* 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: ![](https://1923141441-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F-MFjmFrZ8sef1J7qkr6H%2Fuploads%2FzUfZEHzf2OvGbsJgsiGj%2Fimage.png?alt=media\&token=4f321391-ec7a-4d7d-bcf6-a0077e3f4178)
* Edit the Notifications tab of the Project Settings to define project-wide notifications:![](https://1923141441-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F-MFjmFrZ8sef1J7qkr6H%2Fuploads%2F1jX8bDnoV5lXL6o2aEx8%2Fimage.png?alt=media\&token=077429a2-5dff-4de4-a2be-486e6eceb6a3)