Best reminder apps for iPhone Duo (2026)

On iPhone Duo, start with Apple Reminders. It's free, it's Apple's own app, and its App Store page already lists iPhone Duo among the iPhones it runs on. Every other app here is a reason to leave that default: a reminder that keeps nagging (Due), a planner you buy once (Things 3), projects shared with other people (Todoist, TickTick), tasks that come from Outlook (Microsoft To Do), or reminders that stay in Apple Reminders but carry their next step and can be marked private (Notif, the one I built).

Each app is judged from its own App Store page or site, prices are as of October 2026, and where I couldn't confirm something, I say so.

What iPhone Duo is

Apple announced iPhone Duo on September 9, 2026 as its first foldable iPhone (Apple Newsroom). Closed, it's a phone with a 5.4-inch outer display that Apple says has more than 90 percent of the screen area of iPhone 18 Pro. Open, it's a 7.6-inch display, 50 percent larger than iPhone 18 Pro Max's, and Apple says the two displays share an aspect ratio, so what's on screen scales between them instead of reflowing (iPhone Duo).

There is no Face ID: Apple's specifications list a fingerprint sensor built into the side button. The phone runs iOS 27, pre-orders opened October 16, it reaches stores on October 23, and it starts at $1,999 for 256GB.

What the fold changes for reminders

A reminders app has two jobs: catch the thing fast, and show it back to you at the right moment. The Duo gives each job its own screen.

Closed is the quick glance. The outer display is a normal phone, with the controls along the side so they're easier to reach with a thumb, as Apple's designers put it (Design for iPhone Duo). Typing "call Mom" one-handed, reading the Lock Screen, asking Siri to remind you to drop off the UPS return: all of that happens closed.

Open is the planning view. Apple's announcement says you can run two apps at once in Split View, that the Home Screen shows two pages when open with Today View (your widgets) on the left, and that the new Siri can take one half of the screen while another app has the other. StandBy works on either display even when the phone isn't charging, so a Duo propped on a desk can be a clock or a widget hub (Apple Newsroom, October).

Apps don't all use the inner display the same way. Apple's developer page says apps built with the iOS 26 SDK or earlier "run on iPhone Duo, but won't adapt to all layouts": open, such an app sits in the center of the display with empty space around it. Apps built with the iOS 27 SDK fill most of the inner display, and apps built with the iOS 27.1 SDK or later are what Apple calls optimized for iPhone Duo, extending to the full display. Apple's advice to developers is that on the inner display an app should look like a natural extension of its iPad layout. So an app with a real iPad layout has something to grow into; a stretched iPhone screen stays one.

You can't tell from the App Store. As of October 19, no App Store page I opened carries an iPhone Duo badge, not even Slack's or Netflix's, which Apple named as already updated for the folding design. So for each app below I say what its page states and what it already does on iPad, the closest thing to a preview.

Apple Reminders

Free, built in, and listed for iPhone Duo: Apple's App Store page names iPhone Duo in the list of iPhones it supports. The page describes Siri, a Home Screen widget, smart lists, location reminders, shared lists, Apple Watch, iCloud sync, and Apple Intelligence suggesting tasks from what you're looking at.

The catches haven't changed with the fold. There's no private reminder, because every list lives in an account, and its alerts can be quieter than people expect. Both have their own guides here: private reminders on iPhone and why Apple Reminders don't notify you.

Notif

Notif is the reminders app I built, so weigh this section knowing who wrote it. It runs on iPhone (iOS 18 or later), iPad (iPadOS 18 or later) and iPhone Duo. Every note is a real reminder in Apple Reminders, in Notif's own list. It writes to its own list, never yours. There's no account, and notes are never stored on Notif's servers.

Each note gets an Insight, one line of help, and an Action Button for the next step: the place in Maps, the store nearby, the official page, the booking page, a new email with its subject, the book in Apple Books. On iPhone Duo, open it and Upcoming sits beside your notes; hold it like a laptop and Upcoming sits on top. With Siri, say it and it lands, without opening anything. There's a Lock Screen widget.

Opening a private note asks for Face ID, Touch ID or your passcode, and on the Duo that's Touch ID in the side button. A private note is never sent to Notif's server or to any AI, and marking it private takes it out of Apple Reminders. Like the rest of Notif's data on your iPhone, it is part of your own iPhone backup. Only notes you mark private are private: a note that isn't can be sent, one at a time, to Notif's server and an AI provider to write its Insight, and the privacy page lists what goes with it.

Free gets an Insight a day. Notif Pro is an Insight on every note, smarter Action Buttons and private notes, for $4.99 a month or $39.99 a year, cancel any time. Marking a note private is part of Notif Pro. More in Notif vs Apple Reminders.

Things 3

Things is Cultured Code's personal planner: areas, projects, Today and Upcoming. It's a one-time purchase per platform, $9.99 on iPhone, $19.99 on iPad and $49.99 on Mac as of October 2026, with no subscription (App Store). The iPhone page lists importing from Reminders, which is one way, and says sync comes free through Things Cloud; per Cultured Code's support page, a Things Cloud account needs only an email address and is required only for sync.

The App Store page doesn't mention iPhone Duo, and I found nothing about it on Cultured Code's site. Things does have a separate, full iPad app, the kind of layout Apple says the inner display should extend; whether the iPhone app shows that layout when you open the phone, I couldn't confirm. More in Notif vs Things 3.

Todoist

Todoist is built for sharing: projects as lists, boards or a calendar, shared with anyone and with tasks assigned, recurring tasks, and sync across iPhone, iPad, Apple Watch and Mac plus browsers and email add-ons (App Store). It needs a Todoist account, created with an email address or a Google or Apple account, per its help center. It's free, and Todoist Pro is $6.99 a month or $59.99 a year through the App Store as of October 2026. The page says you can add tasks with Siri.

Apple Reminders isn't mentioned on its App Store page, and I couldn't find an import or a sync in its help center. The page doesn't mention iPhone Duo either; it has an iPad version. More in Notif vs Todoist.

TickTick

TickTick is tasks plus a calendar and habits, with lists you can share. It's free, with TickTick Premium at $4.99 a month or $49.99 a year as of October 2026 (App Store), and its help center says anyone can create a TickTick account for free. Its latest release notes mention creating tasks through the new Siri and new extra-large widgets with more room for tasks and schedules.

It does talk to Apple Reminders, in two ways, both one-way. Its help center says that on iOS, under Settings and then Import and Integration, you can import Reminders directly. There's also an Auto-import from Reminders switch for Siri: with it on, TickTick imports tasks from the default Reminders list every time it opens, and the help page says the original task in Reminders is deleted after each import. Know that before you turn it on. The App Store page doesn't mention iPhone Duo; it has an iPad version.

Due

Due does one thing well: it reminds you again, and again, until you act. Auto Snooze re-alerts every 1 to 60 minutes, and its App Store page describes Home Screen and Lock Screen widgets, Control Center, and adding reminders with the new Siri in iOS 27. The page says there's no account to sign up for, and that the developer doesn't store, and can't access, your reminders and timers; sync is through iCloud or Dropbox. It costs $7.99 once as of October 2026, covering every feature released within a year of your purchase; after that an optional Upgrade Pass, $4.99 a year, adds newer features, and what you've unlocked stays yours.

Its 26.5 release added an import screen for your Reminders lists, one way. The page doesn't mention iPhone Duo; the iOS purchase includes the iPad app.

Microsoft To Do

If your tasks live in Outlook, this is the one that already knows it. Lists sync through Microsoft 365, flagged emails become tasks, My Day is a daily planner, and shared lists tell you when someone changes them (App Store). Microsoft's support page says it's free with a personal Microsoft account, and that a work or school account needs a supported license. The App Store page doesn't mention Siri, widgets, Apple Reminders or iPhone Duo, and its last listed update was in July. It has an iPad version.

Side by side

Who should pick which

• The least to think about: Apple Reminders
• A reminder that keeps buzzing until you deal with it: Due
• A calm planner you buy once: Things 3
• Projects shared with other people: Todoist, or TickTick if you want a calendar and habits in the same app
• Tasks that come from Outlook email: Microsoft To Do
• Reminders that stay in Apple Reminders, carry their next step, and can be marked private: Notif

The honest verdict

Nobody, me included, can show you yet how any of these looks on the inner display with your own reminders in it; the phone reaches people on October 23. Apple Reminders is Apple's own app and Apple lists it for iPhone Duo, so start there. If you already pay for Things, Todoist or TickTick, nothing about the fold is a reason to leave. If you're choosing fresh and want reminders that stay in Apple Reminders, carry their next step, and can be marked private, Notif is free on the App Store: get Notif.

Questions

Do my reminder apps work on iPhone Duo?

Yes. Apple's developer page says apps built with the iOS 26 SDK or earlier run on iPhone Duo but won't adapt to all layouts, so when the phone is open they sit in a centered window with empty space around it. Apps built with the iOS 27.1 SDK or later extend to the full inner display

Which reminder app is best on iPhone Duo?

Apple Reminders is the default: it's free, it's Apple's own app, and its App Store page lists iPhone Duo. Choose another app for a reason it has, like Due's repeat alerts, Things' one-time price, or Notif's next-step buttons and private notes

Does iPhone Duo have Face ID?

No. Apple's specifications list a fingerprint sensor built into the side button, so unlocking the phone, and anything an app protects with biometrics, uses Touch ID or your passcode

Do reminder apps use the Duo's big inner screen?

Only if the developer built for it. Apple says an app built with the iOS 27.1 SDK extends to the full inner display and should look like a natural extension of its iPad layout, while older builds run in a centered window. As of October 19, 2026, the App Store pages for Things, Todoist, TickTick, Due and Microsoft To Do don't mention iPhone Duo at all

Which reminder apps sync with Apple Reminders?

Notif keeps every note as a real reminder in Apple Reminders, in its own list. Things, TickTick and Due import from Reminders one way, and TickTick's auto-import deletes the original. Todoist and Microsoft To Do don't mention Apple Reminders on their App Store pages

How does Notif look on iPhone Duo?

Open the Duo and Notif's Upcoming sits beside your notes; hold it like a laptop and Upcoming sits on top. Every note is still a real reminder in Apple Reminders, in Notif's own list