Custom widgets are specialized user interface elements that developers create to meet specific needs in software applications. Unlike standard widgets, which come pre-built with common functionalities, custom widgets allow for tailored designs and behaviors, enhancing user experience and interaction. They can be used in various platforms, including web and mobile applications. These widgets can include anything from unique buttons and sliders to complex data visualizations. By using frameworks like React or Flutter, developers can easily build and integrate these custom widgets into their projects, ensuring that the application aligns with the desired aesthetic and functional requirements.