Known for do-it-yourself stock and options trading, online brokerage TradeMonster didn't have an easy way for traders to do it themselves on mobile devices.\n\n\nUntil this year, TradeMonster had a clunky mobile platform that didn't work on tablets, says CTO Sanjib Sahoo. "A lot of customers said they weren't opening accounts with us because of that," he says.\n\n\nSahoo nixed the idea of developing native mobile apps for each type of device because that would have produced high costs and maintenance issues. So TradeMonster took a different, admittedly risky route that used HTML5.\n\n\nSahoo says he thought it could fit their long-term mobile strategy if they developed a "hybrid HTML5 app," which wraps the HTML5 Web application in a thin layer of code that provides access to a device's native features but also sends HTML5 code back to the Web server. "We wanted to create a Web-like user experience, and the only technology that is even close to that is HTML5," he says.\n\n\nBut developing in HTML5 wasn't easy. Sahoo and his team wrote a custom framework because, unlike native applications, HTML5 does not have a standard development kit.\n\n\n"[HTML5] is supposedly this universal write-once, run-anywhere application," says analyst Jack Gold, principal at J. Gold Associates. "The problem is that it's not unique to individual devices. You will have to customize code because it has to run in each platform."\n\n\nThe free app was released in February for smartphones and tablets, and an enhanced iPad-specific version (which simulates four desktop screens) was released in June. The app, which has been downloaded 28,000 times, allows users to monitor stock prices and account balances, generate quotes and complete transactions--all in real time.\n\n\nGold doesn't foresee huge growth in trading via mobile devices but says offering a mobile app is a good way to stay relevant with customers. "Giving someone an app won't turn them from three trades per month to 10," he says. "But they expect to have it."\n\n\nSahoo says he's happy they took the risk on HTML5. "My initial reaction was that it may not work," he says. "But it was disruptive [innovation], and I knew we had the business case for it."\n\n\nLauren Brousell is a staff writer for CIO magazine. Follow her on Twitter @LBrousell. Follow everything from CIO.com on Twitter @CIOonline, Facebook, Google + and LinkedIn.