There are two types of dialogs in interfaces: non-modal and modal. Non-modal dialogs appear without disabling content, letting users continue their workflow and sometimes even move or minimize the window.

Modal dialogs, however, demand immediate attention like a traffic stop — blocking the main content until users take action. They interrupt tasks and increase cognitive load, potentially making users forget their previous context. On mobile, modals can appear as:

• Pop-ups
• Partial screen overlays
• Full-screen dialogs

Though intrusive, modals are often necessary to prevent disasters. They're particularly useful for warning users about potential data loss or irreversible actions.^[1]

For less critical information, consider gentler alternatives. Snackbars automatically disappear, while banners stay visible until dismissed or until their triggering issue resolves.^[2]