# 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) --- # Agent Instructions: Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter: ``` GET https://docs.appstrategy.com/apprules-r-documentation/platform-products/apprules-data-migration-engine/validations-error-handling-and-notifications.md?ask= ``` The question should be specific, self-contained, and written in natural language. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.