Once you assign a task to someone, they get a notification on Karo if they have the app. Otherwise, the app first sends them a chat on WhatsApp, and if that fails, a reminder via text message.

A to-do list app called Twos is approaching this problem differently. When you add a task, it can suggest actions that might be relevant.

Microsoft has launched a new to-do list app called Microsoft To-Do, which is available in preview today on the web, iOS, Android, and Windows 10.