Let Duo find your level
When starting a new language, you can take a test to set an appropriate difficulty, and skip whatever lessons you already know.
This helps with the initial habit formation, because the difficulty isn't too easy.
If it were too easy, people might get bored and churn.
Predicted prices
Hopper is a price tracking app for flights and hotels, and it frames the value of a booking by showing a timeline of the predicted prices over time.
A mini celebration
When rating a book 5 stars, you'll see a celebration burst onto screen.
Look at yourself, go on
If you attempt to use a blocked app, OneSec offers a variety of novel interventions, like opening the front camera so you have to stare at yourself breaking your own rules.
Add to calendar
After ordering a food delivery, you can easily create an event in your calendar with all of your slot information and booking reference.
A utility loyalty scheme
Octopus Energy will let you earn Octopoints for completing habit-forming actions (like submitting meter readings), which you can then redeem for credit.
Frequently used emojis
Loom will let you easily swap the default selection of emojis for your most frequently used ones.