Handoff in iOS 8 and OS X Yosemite: Explained

Handoff is a major element of Apple's "integration" theme, and of the new Continuity feature set for iOS 8 and OS X Yosemite, which also includes cross-compatible AirDrop, iPhone call and SMS handling on the iPad and Mac, and the new, much easier to connect, tethering service. Rather than trying to fit one interface across a range of different devices, or making the cloud the center of the universe, Apple is promising to transparently, seamlessly move whatever activity you're doing to whatever device you want to continue doing it with. It's a person-centric choice and a bold one, but if Apple delivers, it could forever change the way we use our iPhones, iPads, and Macs. So, how does Handoff work?

Your iCloud account, your devices

In order for Handoff to work you have to be logged into the same iCloud account on you iPhone, iPad, and/or Mac. That's how Handoff knows those devices all belong to the same person — you. Since your iCloud account (Apple ID) is also used for backup and restore, iMessage and FaceTime, iCloud email and Documents in the Cloud, and a lot more, it's a safe, reliable way to make sure you're really you and your devices are really your devices.

Being logged into the same iCloud account also means that, if you have documents stored on iCloud, they're available on all your devices already, so Handoff doesn't have to waste time and power pushing files around. It only has to push your current activity. (More on that later.)

Bluetooth LE and proximity

Handoff also requires that your iPhone, iPad, and/or Mac be within close proximity to each other. Devices are automagically paired via Bluetooth LE (Bluetooth 4.0 Low Energy) when they come into range and activities are made available for Handoff for as long as they stay within that range.

Enforcing proximity is a good idea and one in keeping with Handoff's person-centric approach. It prevents private websites you're visiting, emails or messages you're composing, or documents you're working on from accidentally getting pulled over to a machine that's logged into your account, but at another location where it's not within your physical control. For example, if you're working at home, you don't need your stuff popping up on a device at school, or if you're at the coffee shop, you don't need it popping up on your work computer.

Proximity allows for both convenience and privacy, the best of both worlds.

Apple apps and Handoff

So far, Apple has announced that Handoff will work with the following apps:

  • Mail
  • Safari
  • Pages
  • Numbers
  • Keynote
  • Maps
  • Messages
  • Reminders
  • Calendar
  • Contacts

With them, you can start composing or reading an email or web site, editing a document, spread sheet or keynote, finding a location, typing a text, picking a reminder, entering an appointment, or looking up an address on your Mac and continue or finish it on your iPhone or iPad, or vice versa.

Apple hasn't yet announced any Handoff functionality for media, for example starting an iTunes playlist on your Mac and continuing it with the iTunes Music app, or starting a game on your iPhone and continuing mid-level on your iPad. Nor have they announced any Handoff features that would let you, for example, push a movie from the Apple TV to the iPad if you wanted to change rooms. (The reverse of AirPlay, which has to start on an iPhone, iPad, or Mac.)

It's still early days, however, and every new feature has to start somewhere.

Third-party apps and Handoff

Apple has provided the same APIs (application programming interfaces) to developers that its using for its own apps. Developers need to specify which discreet actions are available to Handoff — precise activities like composing a tweet or reading an RSS item — and the apps involved all have to be owned by the same developer Team ID. That makes things secure for customers, so we don't have to worry about one app trying to intercept activity from another.

Handoff-capabale apps also have to be made available through the App Store or, alternatively on the Mac, signed by a registered developer. Again, that allows for security, and even a degree of flexibility.

Websites and Handoff

Handoff doesn't only work between apps but also between websites and apps. For example, if you're reading iMore.com or perusing Facebook.com on Safari on your Mac, and then pick up your iPhone to leave the room — assuming the developers have implemented it — the iMore or Facebook app will show up to accept the handoff.

Apple has provided APIs so that developers can prove they own their websites and apps, and that they're all related to each other. That secures both endpoints of the transaction.

To move to the browser, Handoff sends a URL (universal resource locator) from the originating device to the device where you want to resume your activity. Open the browser, load the URL, and you're right where you left off.

To move to a native app, activities specified on the website are sent over to the appropriate location in the associated app. Open the Facebook app, load the page you were looking at, and you're likewise where you left off.

Continuation streams

Apple also says developers can bi-directionally stream between two open instances of the same app on two different devices. That allows for continuous interaction, including read and write, between the original and current device. For example, so both devices to be used to work on the same activity at the same time.

How developers — and Apple — will make use of such streams remains to be seen...

An icon away

Handoff is based on actions. When an app or browser is launched, brought back to the foreground, or tabs are switched, Handoff identifies the current actions you're doing — composing an email, reading a particular web page, editing a Pages document, etc. — and starts to broadcast that activity.

Other devices within proximity identify the activity and call up the appropriate icon for it.

On the iPhone or iPad the icon is placed either on the bottom left of the Lock screen or, if the device is unlocked, to the left of the Home screen in the multitasking card interface (the one you get to by double clicking the Home button.)

On the Mac the icon is placed either to the left of the Dock or to the right of the application switcher (the one you get by hitting CMD + Tab.)

Once the icon is hit, Handoff will request the activity from the originating device. If you're using Documents in the Cloud, only the state needs to be transferred. If you're on the web, only the URL. Otherwise, whatever you're working on will get sent across. Once any necessary data is passed (presumably over direct Wi-Fi connection), you're taken to the app and your activity is resumed right where you left off.

For example, if you were composing an email on your iPhone and you walked within range of your Mac, the Mail.app icon would appear in a new segment to the left of your OS X Dock. Click on it and you'd be in OS X Mail, in the compose window, with the same email open and ready for you to finish, right where you left off.

If you were working on a Keynote on your Mac and you picked up your iPad, you'd see the Keynote app icon to the bottom left of your Lock screen. Hit it and you'd be taken to the Keynote app on the iPad, the same document open to the same slide you'd just been working on.

Security and privacy

Apple hasn't yet released any information on how Handoff is secured and kept private. However, given Apple's recent history with security and privacy, there's every reason to be optimistic. For example, Apple has previously explained how AirDrop, another service now marketed under the Continuity banner, handles security and privacy and it's beyond impressive:

When a user enables AirDrop, a 2048-bit RSA identity is stored on the device. Additionally, an AirDrop identity hash is created based on the email addresses and phone numbers associated with the user's Apple ID.

When a user chooses AirDrop as the method for sharing an item, the device emits an AirDrop signal over BTLE. Other devices that are awake, in close proximity, and have AirDrop turned on detect the signal and respond with a shortened version of their owner's identity hash.

[...]

The Wi-Fi radio is used to communicate directly between devices without using any Internet connection or Wi-Fi Access Point.

Also, since Handoff appears on the Lock screen, how passcode, Touch ID, and enable/disable will be handled in Settings remains to be seen. (It's possible BT LE and proximity is allowing Handoff devices the potential to be treated as trusted devices for security purposes.)

Resources for developers

Apple has a preliminary Handoff Programming Guide available on the Apple Developer center that explains in greater detail how Handoff works and how it can be implemented in third party apps.

There's also an excellent Adopting Handoff in iOS and OS X session available as part of Apple's WWDC 2014 video collection.

Bottom line

Handoff promises a fundamentally different approach to computing than Microsoft's "Windows Everywhere" or Google's "everything in the cloud". With Handoff, there's no convergence of interface or single truth kept on a server. Apple is keeping the Mac the Mac, and the iPhone and iPad the iPhone and iPad. They simply all integrate together so that your activities can go from device to device transparently, seamlessly, wherever you go.

At least that's the theory. iOS 8 is still in beta. Things aren't finished yet and they can and will change as Apple approaches release. So, we'll have to wait for this fall to see how Handoff really works.

Rene Ritchie

Editor-in-Chief of iMore, co-host of Iterate, Debug, Review, Vector, and MacBreak Weekly podcasts. Cook, grappler, photon wrangler. Follow him on Twitter and Google+.

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Reader comments

Handoff in iOS 8 and OS X Yosemite: Explained

30 Comments

I have a mid 2010 MacBook pro that does not have Bluetooth LE I believe. Does that mean Handoff will not work with my iPhone 5S? Can I enable it using a third party Bluetooth dongle or will Apple disable Handoff at a hardware level for non supported Macs?

Bluetooth LE or 4.0 is backwards compatible. So it will work with any previous version of Bluetooth.

So if I understand you correctly, and the specs of HandOff... It ISN'T hardware specific? I have an iPhone 4s, mid 2009 iMac and MacBook Air 2012 - none of them are showing Handoff. Running the DP1 of Yosemite and Beta 1 of iOS 8. Figured it was the old hardware.

I hope I'm wrong but I think it only works with bluetooth LE. It's like that app (sorry I'm blanking on its name) that pairs up with your phone via bluetooth LE and unlocks your Mac when in close proximity.. So, I believe my Macbook Pro 2011 and before won't have handoff etc..

It's unclear because there's both Bluetooth LE and direct ad-hoc Wi-Fi involved, I think, and both of those require specific radios.

We'll have to wait and see if there's a compatibility list anywhere.

I wonder why Apple doesn't provide developers with at least a preliminary listing of which Continuity features are expected to work with which devices (perhaps with a footnote advising everything is subject to change, etc.)

A lot of people may be needlessly wasting time testing features on unsupported devices that could be better spent elsewhere.

Here are the Macs that will be able to support Continuity:

MacBook Air (Mid 2011 or later)
MacBook Pro (Mid 2012 or later)
Retina MacBook Pro (All models)
iMac (Late 2012 or later)
Mac Mini (Mid 2011 or later)
Mac Pro (Late 2013 or later)

What's interesting is this represents a big shift within Apple as not once did they mention the post PC era at WWDC. This is very cool technology and I'm curious to see how it evolves.

I'm struggling to understand what your comment even means. *What* represents a big shift? What do you mean "They didn't mention the Post PC era"? What do you glean from the fact that they didn't (if they didn't)? What does *any* of that have to do with Bluetooth and Handoff? I can't think of any set of answers to these questions that makes any sense at all.

I mean, if all you mean is that because they didn't say the words "Post PC" and because this technology is for PCs as well as mobile devices, that this represents a "big shift within Apple," that's just crazy talk. Completely unsupportable.

Not at all. This is the first year Apple has embraced the PC at the same level as mobile. Why would a company dedicated to moving past the PC era care about a technology such as Handoff? Clearly something has changed.

This also works with gefencing... I noticed, when I went into Safeway and pulled out my phone to find my shopping list (which happens to be in Reminders.app, not Safeway.app), there was a faded out Safeway logo in the lower left-hand side of the lock screen. I swiped up on it, and it took my right into the Safeway app. It was awesome! This has definitely encouraged me to look for, and download, any apps which a business may have. I could imagine this working beautifully with the BJ's (restaurant) app, which is awesome, by itself. On a side note, if you have a BJ's near you, you need to download their free app.... it let's you place yourself on their waiting list, order your food and pay, all from withing the app itself. We were in and out in 35 min.... exceptional!

I need to work out how to fit this into my ipad usage model. My ipad is in a smart case, and so the screen is either covered, or auto unlocked when I uncover it. Therefore I don't get the chance to swipe on the handoff symbol on the bottom left of the screen.

Hmmm...I'm on IOS 8 beta 2 using the Iphone 5 and a Ipad Mini wifi version only with IOS 8 Beta 2 as well. I have bluetooth turned on for both devices, both logged in to the same icloud account and I don't see anything for handoff?

I started a email on my iphone but I cant do anything handoff wise with the ipad? I opened up the multitasking app and nothing is there beside the usual stuff. Do I need to actually connect to my ipad in the bluetooth settings for my iphone?

i hate having bluetooth on all the time. Even LE still kills battery searaching non stop for devices.

Is Handoff active in the iOS and OS betas out now? If so, is there a way to activate it or is it automatically on?

I have a 11 inch MacBook Air Mid 2011 and a iPhone 5s and the handoff feature isn't working for me. Ive check the specs and I have BT 4.0 on my mac. Only feature that works is iMessages. All my sms are syncing to my mac and occasionally i can send an sms from my mac. I can see my iPhone 5s hotspot but i can't connect to it

Perhaps the Handoff feature isn't fully operation with the first betas? I'll ask again if Handoff has to be activated or if it's automatic. If it has to be activated on all devices, how is that done?

PS - Sad about the spam. I agree - iMore needs a report button.

I just setup handoff on my rMBP and iPhone5 and it works like a charm! It took me a min to realize that you actually have to turn on the feature in Preferences>General but after that it works perfect! Can't wait for the GM and more apps to work with this feature!

Other than turning on the feature in system preferences, what did you do? 'Cause I did it too but I can't get it to work. Do I have to enable it on my iPhone 5 as well? I can't find the way to do it.

So, is anybody going to tell Apple that this already exists and works with far better software than what they're peddling?

reallly feeling splendid to hear that we can use third-party apps with Hand-off.Thanks to Apple.Also a good article on pre-release speculation.

I've tried everything and cannot get handoff to work between my iPhone and iPad. Bluetooth is turned on on both devices, they are on the same networks and both signed into the same iTunes account. I don't see anyindication it exists in the app switcher and no icon on my screen indicating the other device.