Daylio is a mood and goal tracker, with a primary focus on mood tracking. When the user opens the app up, they see five emoji. If they have customized their moods, there may be some other emoji to choose from. The user chooses the emoji that matches their current mood. The app then shows the user a screen to log their activities (such as work, a date, a party, or good food).

The app also provides a variety of different graphs and calendars to help the user identify patterns that connect certain moods with certain activities. The user makes notes in their journal entries if desired. For those who want to use it, there is also the option to set goals (such as water intake or exercise).

There are premium features available for purchase in-app. The ESRB rated Daylio E for Everyone and LW4K stands by this rating. Younger users may need help getting the first couple of entries done, but thanks to the use of emojis, this app can be used by just about any age.