FormType

formType is a general term used in software development to describe the abstract specification of a form: its fields, their data types, validation rules, and how input maps to an application data model. A form type serves as a blueprint that can be instantiated, rendered in the user interface, and processed by server-side or client-side logic. By encapsulating structure and validation, form types support reuse and consistency across views and endpoints.

Typically a form type defines a collection of form controls (fields), each with a type (for example, text, number, date), options such as required, label, placeholder, and constraints or validators. It may also include nested or composite forms, allowing complex data structures to be captured in a single submission. Data mapping merges submitted values into a model object or data transfer object, with normalization and transformation rules.

As a practical pattern, form types are common in frameworks that implement a form builder or form component system. In Symfony's Form component, for example, a form type is a class that declares fields in a buildForm method and configures default options in configureOptions; it can be extended or composed and reused across controllers or services. Rendering typically delegates to templates, while submission is handled by a form handler that validates according to the declared constraints.

Alternative names exist, such as form schemas or form builders, depending on the framework. The central idea remains: separating form structure and rules from presentation and business logic to improve maintainability, testability, and consistency.