Can developers write their own validations in OutSystems?

In OutSystems, developers have the flexibility to implement custom server-side validations. This is essential for ensuring that the data processed by the application adheres to the necessary business rules and integrity constraints. Custom server-side validation allows developers to define specific validation logic that can be executed when data is being saved or manipulated, providing a secure layer to enforce rules before data is persisted in the database.

This capability is particularly important as it helps prevent invalid or harmful data from being stored, improving the overall robustness and reliability of the application. Moreover, because server-side validations operate on the backend, they provide an added layer of security, as client-side validations can sometimes be bypassed by users.

While client-side validations are also possible in OutSystems, they are primarily aimed at improving user experience by providing immediate feedback to users as they fill out forms. However, since the question specifically regards where developers can write their own validations, focusing on the server-side aspect is critical for maintaining data integrity and security. The other options do not accurately capture this essential feature of OutSystems, emphasizing the correct choice regarding custom server-side validation.