There’s an entire slew of new features available in iOS9 — but there’s one that you’ll be using every single day. It’s called Go Back to App and it’s all over the place. If you open an app from another app, instead of doing a full “flip” like you tapped the home button, iOS slides the app in and you get right to work. It happens so smoothly that it’s hard to even see happen:

This is going to change how iOS apps are made. Combined with Universal Links for opening up http:// and https:// links from Safari (or anywhere) inside your app, the reality for how apps are opened and work together has forever been altered. I know Apple loves calling features amazing — but this time they’re right.

It’s not just for apps. Back to is baked deeply into iOS. If you’re in Spotlight looking for something on your device, you’ll get brought back there. Here’s a preview of the new CoreSpotlight APIs working with the Basecamp 3 app:

It seems so simple, but I can guarantee you’ll be using it several times a day. It didn’t click for me until I tried out Facebook and Messenger. I’ve been using Paper since its release, but I decided to give the main Facebook app another chance after the iOS9 upgrade.

The middle icon — the most prominent one — of Facebook’s tab bar is Messenger. Jumping to another app in iOS9 makes this experience immensely less jarring, and well, smooth:

Back to is going to enable a new class of iOS apps. It’ll break up monolithic apps around a service into smaller apps that are easier to update, maintain, and conceptualize for users. It’s not a huge pain to flip to another related app. The worry about “oh, did they install that app?” still exists as a developer, but once installed, it’s super smooth.

I’d love to see this change promote a “fleet” of apps around services that each do one thing well instead of one app that does many things. Many services are there already. I’m confident more apps will ship in the next year that fully embrace Back to. It’s these under the hood, almost invisible changes that I love most about Apple’s polish and design. I can’t wait to see more.

This article was originally posted on our Medium publication, Building Basecamp 3.