Kik at 50M users: Who needs Facebook Home when you can build an in-app platform?

The popular mobile messaging company Kik isn’t sweating Facebook Home.

Kik announced today that it has reached a new milestone of 50 million registered users, up from 30 million in November, with more than 200,000 people joining every day.

The big draw? Simple HTML5 apps, called Cards, which Kik added to its iPhone and Android apps last November. Since you don’t have to leave Kik’s app to use the Cards, they’re a sly way for the company to keep its app in front of your face for extended periods.

“This is where you see why we went with Cards. It’s an integrated web app experience, rather than a native platform, because it gives us full control,” said Ted Livingston, Kik’s founder and chief executive, in an interview with VentureBeat. “With Cards, the goal is to have more and more of your apps inside of Kik.”

The company can also update Cards without waiting for app store approval as well as easily deploy new Cards across its apps on multiple platforms, since they’re built in HTML5. Kik says that its users have installed more than 25 million Cards so far.

Kik initially launched with apps for viewing YouTube videos, searching for photos, and sketching together with your friends, but now it has a Card for viewing Reddit as well as a game called Squared that’s become surprisingly popular. Squared, which was written in a single weekend by a Kik employee for fun, saw over 1 million downloads in four weeks, and it has racked up the equivalent of more than 60 years of gameplay so far.

Kik’s approach with its in-app platform is sort of like an inverted version of what Facebook is trying to do with Home, an Android application that lets Facebook take over your phone’s interface.

Kik’s big advantage is that it can actually deploy its platform to the iPhone — while there’s pretty much no chance in hell Apple will allow something like Facebook Home on the iPhone. That cross-platform compatibility was far more important to the company than completely taking over someone’s phone, Livingston told me.

He found at least one thing to like about Facebook Home. “Chatheads is definitely interesting — awful name, but pretty compelling experience,” Livingston said.

With new versions of Kik’s apps launching today, the company has added its own HTML5-powered in-app push notifications, which lets you preview messages and updates to your Cards, without navigating away from your current screen. The company notes that it’s one of the first to pull off push notifications with HTML5 (one of the biggest problems with pure HTML5 development, which competitor Chorus.im is also dealing with).

Kik’s biggest cross-platform competitor is Whatsapp, which just recently squashed a rumor about a $1 billion Google acquisition. Livingston noted that “it would be fantastic for us” if Google bought Whatsapp, because there’s a good chance the search giant would just shut down the app and try to assimilate its users and technology.

He also doesn’t worry too much about Whatsapp as a competitor (which is said to have more than 100 million users):

They’re much bigger today, but they have much weaker network effects. They’re not a product company … half their users are on crappy feature phones. They’re waking up to this idea that it was all about the messenger, but now it’s about the platform around the messenger. … They’re in no position to compete at the platform level.

Based in Waterloo, Ontario, Kik raised $8 million last year from RRE Ventures, Spark Capital, and Union Square Ventures.