# Custom Extensions Page Designer provides built‑in support for **Custom Extensions**, enabling developers to create and integrate **user‑defined components** directly into the design environment. Custom Extensions allow teams to extend the default component set with reusable UI elements that are tailored to specific application requirements. *** #### **Purpose of Custom Extensions** Custom Extensions are designed to: * Introduce specialized UI components not available by default * Reuse custom UI logic across multiple pages or applications * Encapsulate complex UI behavior into manageable components * Maintain consistency in look and behavior across applications Extensions can be developed independently and plugged into Page Designer as needed. *** #### **Platform Scope** Custom Extensions can be developed to target specific platforms: * **Web Applications** * **Mobile Applications** Each extension is platform‑specific, ensuring optimal behavior and performance in its intended runtime environment. *** #### **Extension Development Model** Custom Extensions: * Are developed by users or development teams * Are registered with Page Designer as reusable components * Appear alongside built‑in components in the designer palette * Can expose configurable properties for design‑time customization This model allows extensions to behave like native Page Designer components. *** #### **Learn More** For detailed information on creating and using Component Extensions, refer to the dedicated documentation: > **Component Extensions**\ > *** #### **Summary** **Custom Extensions** empower developers to expand Page Designer beyond standard UI capabilities. By supporting user‑defined components, ONEWEB enables: * Greater UI flexibility and extensibility * Reuse of custom functionality across applications * Cleaner page designs through component abstraction * Support for advanced and domain‑specific UI requirements This extensibility ensures that Page Designer can adapt to a wide range of modern application use cases while remaining structured and maintainable. --- # 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.onewebstack.com/oneweb-platform-th/building-apps/ui-page-designer/ux-ui-customization/page-customization/custom-extensions.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.