Best Apps for iPhone Duo: What to Look For Before You Install

The best apps for iPhone Duo are the ones designed for both of its displays: they feel natural closed, they use the large inner display well when open, and they keep your place when you switch between the two. Before you install anything, check for those three things.

iPhone Duo goes on sale October 23, and developers have been preparing apps for it since Apple opened submissions. Here is how to tell which ones are worth your home screen.

1. It works well closed

Apple says (Apple) the outer display has more than 90 percent of the screen area of iPhone 18 Pro. That means most of your day can happen with the phone closed. A good iPhone Duo app should feel complete on the outer display, not like a cramped version of its open layout.

Test it: use the app closed for a full day. If you keep opening the phone just to do basic things, the app is not built for it.

2. It uses the inner display, not just stretches

The inner display is 7.6 inches, which Apple says (Apple) is 50 percent larger than iPhone 18 Pro Max. Stretching a phone layout across it wastes that space. The best apps add something when you open them: more context, a second panel, or a wider view of the same information.

Good signs:

• Content that continues naturally when you open the phone, instead of jumping or reloading.
• Extra detail or a second view that only appears on the larger display.
• Controls that stay in the same place, so you do not have to relearn the app every time you open it.

3. It keeps your place when you open and close it

Apple describes the switch between displays and orientations as seamless. Apps should match. If you are halfway through a list or a document when you open iPhone Duo, you should land in the same spot, not back at the top.

This matters more than it sounds. You will open and close the phone dozens of times a day. Any app that loses your place each time will wear you out.

4. It plays well with Split View

Apple says iPhone Duo supports Split View multitasking, so you can run two apps side by side. Apps that handle a narrower window gracefully are far more useful here. Think of the pairs you use together: a plan next to email, notes next to a document, a recipe next to a timer.

5. It suits the poses you will actually use

Apple shows iPhone Duo closed, open in portrait and landscape, seated on a table and standing on its own. Ask which of those you will use with each app. A planning app earns its place open in portrait. A video or workout app shines seated or standing.

Start with what Apple built in

Before you install anything, try the features Apple designed for iPhone Duo. They show you what a well built app on this phone feels like, which makes it easier to judge everything else.

• StandBy. Apple says you can use StandBy even when iPhone Duo is not charging, turning it into a clock, a photo frame, or a display for your calendar and widgets.
• Widgets. A glanceable widget on the outer display can answer “what is next” without opening any app at all.
• Hands free calls. Because iPhone Duo can stand on its own, a video call no longer means holding the phone up.

Once you know how these feel, any third party app that feels clumsy by comparison is easy to spot.

The categories that gain the most

• Planning and to do apps. Seeing a whole goal and its steps at once is the biggest upgrade a larger display gives.
• Reading and writing. A wider page means less scrolling and easier editing.
• Photo and video tools. Apple has built camera features that use the outer display as a live preview for the people you are photographing.
• Anything you use side by side. Split View turns two apps into one workspace.

Where PathRank fits

PathRank is built for iPhone Duo, and its iPhone Duo version is on its way to the App Store. Closed, it is designed to work like the phone app: capture a brain dump by voice or text and see your next Ready task. Open, your plan continues across the larger display with the same navigation, so nothing moves when you open or close the phone.

You describe a goal and PathRank turns it into a prioritized plan, with steps sorted into Ready, Prep, Research and Blocked phases and dates only on what you can do now. The Command Center shows what needs catching up and what matters today. If you want to see how the method works first, read our guide to breaking a big goal into steps.

A quick checklist before you install

• Does the App Store page say it is built for iPhone Duo?
• Do the screenshots show both the closed and open layouts?
• Does it keep your place when you open and close the phone?
• Does it work in Split View?

Four yeses, and it is worth a spot on your home screen.

Before you install anything, check the running list of apps not yet optimized for iPhone Duo and our read on what makes an iPhone Duo app work on the inner display. Every PathRank guide for the new phone is collected on one page: PathRank on iPhone Duo.