Chances are, when I say the term "offline-first" apps, you will go like "huh🤔 what's that". And If you just did that, let me introduce you to this exciting new idea of building apps, that work for everyone(doesn't matter if you have a internet connectivity or not).
But Wait a minute, all apps on my phone work alright with or without internet. What's new in this ?
Well, that's a correct observation, and this is often the case that trips people while thinking about offline-first apps. How are they any different from apps like calculator, notes, etc.
Apps like calculator, notes, etc are what is knows as offline apps, because of the property of having no dependence on your internet connectivity. But with offline-first apps, users need to connect to internet every once in a while for the app to function correctly.
Let look at an example, Imagine we have an app like Netflix, which is primarily a streaming platform, i.e users need internet connectivity to be able to use there platform. Now, say that they want to expand into countries, where either internet is not available at all, or the internet speeds are just too slow, or the prices are just to high. So to take there business to a place where users don't have consistent internet connectivity, they would have to change there app architecture to support working without internet.
This theoretically can be achieved by an offline-first app. They can keep, a selection of say like 10 movies within the app and when the user is done watching those, then they can connect to the internet and can get more videos.
Now the example above might not make complete sense in terms, like this is exactly similar to downloading movies. But for some companies this makes more sense. Take for example uLesson, which is an eLearning company, operating in Western Africa Regions, they ship data dongles to there customers, which has the learning material. Students can learn, give tests, take exams, etc. After a set amount of time, the user has to connect to the internet briefly to sync there progress, get new content, etc. For them, the offline-first app model makes sense, since without it they can't reach there customers.