Since the salvos of rocket attacks from Gaza began, a huge number Israelis and supporters of Israel around the world have been relying on the “Red Alert: Israel” smartphone app to notify them in real time of rocket siren warnings all over the country. Now, developers in Israel and abroad are offering alternatives to Red Alert, tweaking the original app that sounds an alarm each time Hamas fires a rocket at Israel.

In the case of iRon Dome, says 19-year-old developer Arik Sosman, it calculates the projected impact area in the so far unlikely event that Iron Dome, the Israeli defense system that gives the new app its name, misses. Another tweak is inclusion of a comprehensive map of all present and past rocket alerts in Israel.

It improves on Red Alert by localizing possible rocket strikes and differentiating between an immediate threat to the user and rockets aimed elsewhere. Though Red Alert users can single out one place to watch — presumably where they live — it also sounds identical alerts for all places in Israel, making it ideal for foreign observers but somewhat nerve-wracking for Israelis.

Sosman, born in Tel Aviv, moved to Germany with his parents when he was five years old. While studying math at a university in Hannover, his passion for programming brought him last year to the Apple Worldwide Developers Center (WWDC) in San Francisco, where he met another young Jewish developer, Ben Honig. After WWDC, the two kept in touch via Facebook.

“Both Ben and I share an interest in Israel. I go there once or twice a year,” said Sosman. Even though he does not live in Israel anymore, most of his family and friends do, so he felt the urge to help with the daily dangers facing Israeli population from constant Hamas rocket barrages.

“Sometimes when I speak with my relatives and friends on the phone, a siren sounds and they have to take cover,” he said.

Last week, when Sosman decided to create “iRon Dome”, he sent a message to Honig, asking whether he was interested in working on the project.

Honig, a 22-year-old information science student from New Jersey, immediately accepted the proposal. For a week, the two youngsters, one in Germany and the other in the US, worked remotely on the app. “When Arik was sleeping, I would be coding. When I was sleeping, Arik would be coding,” said Honig, referring to the time difference between the two countries.

In a matter of a few days, the app was created and launched on the App Store.

“iRon Dome tracks your location and, upon detecting a siren, sends you a distinctly agitating and annoying notification, so that if you’re in an affected area, you know to seek refuge in a safe place,” said Sosman. “The map on the app provides a visual of the affected areas by creating a circle around the estimated point of the impact. Otherwise, you get an audible but non-urgent alert.”

The app’s map component gives it a strong visual component. It’s designed specifically to help Israelis deal with emergencies, rather than to inform users from abroad about the incoming rocket attacks. Moreover, “iRon Dome” – at the moment available only for iOS – keeps track of past rockets and estimates the potential impact zones.

It’s also faster than Red Alert, say the two developers. Red Alert takes up to 30 seconds to send a message after a siren starts blaring.

Honig, who designed the app, is helping promote it through social media. He posted the link on his Facebook profile, and the members of his fraternity at Syracuse University shared it. “Even though it doesn’t seem so, America stands with Israel,” he said.

“I wish for everybody to stay safe and not to have to rely on our app,” added Sosman.