Please suggest when to use and when to not use modal popup in the responsive application. Is it good practice to use modal popup in a responsive application with large mobile user base? what are alternatives?
Be cautious when using modals. They have some disadvantages. For example; when presenting users with a modal popup, you take them away from their current task. They might forget their task and the popup might block important information in the background.
There's a great article by Nielsen Norman Group on modals and when to use them. They present you with guidelines on when (and when not) to use modals and some alternatives. Good luck!
Modal dialogs interrupt users and demand an action. They are appropriate when user’s attention needs to be directed toward important information.