The Financial Times has launched a new, subscription-based iPad app, but you won’t find it in Apple’s App Store. The app is a touch-optimized, HTML5-powered newspaper that runs in the browser.

And it’s slick. Open app.ft.com in Mobile Safari and you’re prompted to add a bookmark to your home screen, which unlocks the site’s full potential. The app launches full-screen, unencumbered by browser chrome. It’s fast and smooth. Stories are downloaded, which allows for offline reading.

In other words, the FT’s web app is practically indistinguishable from a native app.

That’s important, as Peter Kafka notes, because it allows the FT to deliver a “native” experience without having to play by Apple’s subscription rules. But it will become much more important, and interesting, if the newspaper pulls its existing apps out of the App Store next month, when Apple’s policy will become a Hobson’s choice for all publishers. At that point, Apple will demand a share of the publishers’ proceeds and keep valuable subscriber data to itself.

The FT’s promotional video opens thusly: “The FT app is moving.” And it seems to promote the web app’s advantages over its predecessor, the native app. “The app is quicker. You can now read more content and watch our award-winning video on iPhone as well as iPad,” the narrator says. The web app, in other words, could well be a test case for paid content that does its thing outside the confines of Apple’s walled garden. Though the FT says it has “no plans to pull out of any apps store,” Kafka notes, he continues: “That’s not the same as saying it plans to stick around, either.”

Pulling out of the App Store (and, soon, the Newsstand) would mean forfeiting real estate in a clean, well-lighted place. Apple’s one-tap subscriptions could not be any simpler, unless and until someone invents thought-controlled tablets. Then again, the FT serves a niche audience, and an audience that knows how to find it. (As of April, it had nearly 600,000 paying subscribers.) It doesn’t need the discovery function of the Newsstand or App Store in the same way that a more general-interest publication does. It’s not like USA Today is shunning Apple in favor of the open web.

So the FT’s web app could be less about shunning Apple and more about working with it: keeping one foot inside Apple’s garden, and the other outside. If so, the FT isn’t the first to try this approach. Take NPR, which was among the first to launch a tablet site, and whose native app is also enjoying wild success in the App Store. (It surpassed 1 million downloads in April.)

Perhaps a better example is The New York Times, whose website offers HTML5 video and tablet-style swiping between articles. (The website is frequently featured in Apple’s own promotions of Mobile Safari.) The Times’ native app, on the other hand, is consistently among the top-rated news offerings in the App Store. Even though the Times has to give something up to get its product in both places, 70 percent of a subscription sale is better than 0 percent.

I don’t know if I would even call the FT’s move an “end-run,” since Apple encourages developers to build web apps and promotes Safari as a open-standards browser. Apple is not stopping anyone from innovating outside its walls. It’s saying, If you want access to our 225 million credit cards, you have to play by our rules. Sure, Apple would probably prefer to have the FT’s apps (and subscribers) inside its garden, and the FT may have found a clever way to have it both ways. Then again, the FT is still tailoring the experience for one device — the iPad — so Apple is not exactly smarting.