What the Hell is CardDAV, Anyway?

If you’re someone who actively manages your contacts on a computer or mobile device, you might have heard the term “CardDAV.” More importantly, if you’re an Apple user who wanted your iOS or OS X Contacts to immediately sync with your Google Contacts – and were confused when they didn’t – CardDAV is the solution.

If you’re like me, you hold CardDAV in the same part of your brain that handles concepts like the Infield Fly Rule in baseball. Meaning:

  • smart people keep mentioning it to you as if it’s really important
  • you secretly have no idea what it is
  • but you find yourself wanting to use it in conversation, to show that you’re technical.

Here’s the skinny on what CardDAV is and, more importantly, how it can help you.

Open Protocols, Bartenders, and Tibetan Monks

CardDAV is an open Internet protocol (or standard) for syncing contacts, like IMAP for email and CalDAV for calendars. It’s built around the HTTP-based WebDAV protocol and uses vCard format for contact data. “Open protocol” is just nerd speak for a standardized method of handling a common procedure. For example, if you and a bartender had an open protocol for greeting each other, it might look like this:

  1. You stare at the bartender, holding money in your hand.
  2. The bartender makes eye contact with you, letting you know he’s ready for your order.
  3. You tell the bartender what drink you would like.
  4. The bartender pours that drink and hands it to you.
  5. You give him the money.
  6. He gives you change.
  7. You tip him.
  8. Billy Joel’s Piano Man begins playing on the jukebox.

This is an oversimplification, but you get the point. If either one of you takes an action out of order (except Piano Man), the whole process gets screwed up. Hence the benefit of standardizing the protocol. The “open” part refers to the fact that the protocol is published and everyone knows how it works, much like how to order a drink at a bar.

Standards such as CardDAV are created by a group of web-savvy monks who sit high on a mountain in Tibet drinking tea and meditating these issues all day. At least, that’s what I like to believe. In reality, CardDAV was devised by the Internet Engineering Task Force (IETF), which is a group of engineers organized into various committees and task forces to set various standards and protocols. You probably don’t care about that, though. You only care about whether it works and how it helps you.

How CardDAV Helps You, Already!

The reason why your iOS contacts didn’t immediately sync up with your Google Contacts after you setup your account is that the default method for account creation doesn’t sync contacts. You have to setup an “Other” account on your device for CardDAV, to start syncing.

It’s worth noting that, until recently, Google didn’t support CardDAV. They do now, which is awesome and keeps you from using the old way via Microsoft Exchange ActiveSync (which Google no longer supports, anyway). We hope Apple makes things even simpler in the future, so you can just check a box to sync your contacts.*

In the meantime, if you need instructions for setting up CardDAV on your iPhone or other Apple device, check out this link. Note that this requires iOS 5 or higher. To setup CardDAV in OS X, here are instructions.

Boom! You’re in business, and you can now consider yourself a CardDAV wizard.

*UPDATE: Google and Apple have now collaborated to make CardDAV setup a much easier process. As it now stands, you can set up CardDAV simply by adding a new Google account on your iPhone, iPad, or Mac, and turning Contact Syncing to “On.”

Additionally, adding CardDAV contact syncing to Android is now as simple as connecting a new Google account to your Android device. Your contacts will now sync with CardDAV automatically.


Oh yeah, and in case you’re interested, here’s an explanation of the Infield Fly Rule. I confess that I had to read it before writing this blog.

What did we forget to mention? Let us know!

Beer: Derek Key via Flickr