7 app ideas from easy to insane

1. Contact app

This is perfect for your first real app. Just a simple app to edit  , save and delete contacts. if you are a complete beginner , you can try this with shared preferences , but if you want to do it the right way you should use an Sqlite database

2.Who owes you what

Another simple app could be one that tracks who owes you how much money and how much money you owe other people.
if you want to put this on the next level , you can connect it with the contact app to be able to select contacts from there.

3. Note taking app with Firebase Sync

A very useful app would be a note taking app that will regularly backup your notes online . you can easily use Firebase Firestore or realtime database for that . to put this on the next level, you could use your own server and own database  .

4. Graphical Restaurant reservation 

this is useful for a lot of restaurants and you could probably be able to earn some money with that if you do it right . or you could just invent  you own restaurant and do it for yourself for learning purposes

5. Instant messenger

Something like a simple WhatsApp clone is more intermediate , but absolutely make able. you could either use one of the Firebase databases for that or do it like real chat apps do it and send your messaged via a server to the other device .6- IOT Manage your home app
if you have some iot devices at home , you could develop an app on your own that is able to control them , what would also be cool is having a raspberry pi at home that is able to control your home even if you're away .

6. Stock Prediction app

You could use AI in combination with public stock Apis to try predict stock prices. even better : implement an automatic buyer and seller of the stocks . but you need some balls and confidence in your AI for that

7. Document scanner with automatic organizing

This is super hard . what i mean by this is an app that scans documents with the device's camera and uses an AI to detect the content of that scanned document , so it can automatically put it into the right folder . if you are able to do such an app , you are truly a genius.