As the sun sets on Friday nights, observant Jewish children race to type out their last text messages, parents dial last-minute calls to elderly relatives, and then many observant Jews power off their mobile phones and other devices and tuck them away for 25 hours of electronic silence.

A screen shot of the Shabbos App website.

For Jews, observing Shabbat means not using electricity on the Jewish day of rest – which until now has meant, no cellphones. But now a team of tech-savvy rabbis and software programmers say they will change that with the Shabbos App, a smart phone application that they say allows use of the device without violating Shabbat restrictions.

“There is a lot of controversy around this,” said Shabbos App developer Yossi Goldstein. “But there are people who are excited about it.”

Excited, maybe. Skeptical, definitely.

“That’s impossible,” said 16-year-old Schneur Shuchat, taking a step back when he heard about the app, which its creators say they will launch next February.

A Yeshiva student growing up in Crown Heights, Brooklyn, Shuchat has never used his phone on Shabbat. “That’s not so good. That’s not so kosher,” he said, explaining that in his largely Hasidic neighborhood it is frowned upon to use a phone on Friday night and Saturday.

Which may explain why many, like technologist and entrepreneur Rabbi Jason Miller, wonder if the Shabbos App is a prank.

“It certainly violates the letter of the law,” Miller said. “We have become so dependent on our mobile devices, so it is becoming hard to put them aside for 25 hours. But ultimately rabbis are not going to support the app.”

The Orthodox Union, one of the worlds most recognized kosher certifiers, called the application “ludicrous” on the organization’s website.

But several news organizations serving the Jewish community have reported on the app and the announcement that it will be sold on the App Store and Google Play for $49.99.

Hareetz, one of the largest newspapers in Israel, called the app a new option for “Sabbath-observant Jews who can’t keep their cellphone addictions in check.”

Blogger Julie Sugar of the Jewish Daily Forward argued that not everyone practices Shabbat in the same way, explaining that the app might be a good option for some Jews who already struggle to observe Shabbat.

“Whether peace of mind of any sort can be purchased for $49.99 is perhaps dubious, but we’re making a grave mistake when we judge someone who is already struggling with Shabbos and is seeking a kosher balance,” Sugar said.

Despite the widespread media coverage, a Kickstarter campaign for the Shabbos App has drawn pledges from only about 50 people, for a total of $2,000.

And on social media, reception of the idea has not been particularly kind. One Facebook commenter on the app’s page said, “$49 a unit might seem expensive, but for a ticket straight to gehinam,” or hell, “it’s actually quite cheap.” Other Facebook users called the new app a “trap” and a “scam.”

Its inventors insist it’s real, though, and they say the software they have developed is all in line with Jewish law, including the Torah restriction that Jews may not light a fire on Friday night and Saturday. That rule is widely interpreted as prohibiting turning on a light, or in this case illuminating the screen of a smart phone.

To deal with this stipulation, the Shabbos App keeps the phones’ screen lit continuously, until Shabbat is over. Critics argue that this contradicts the widely held belief that Jews should stop all use of electricity on Friday night and Saturday.

Although the application is causing some controversy, similar concepts have sprung up over the years and become widely accepted.

Some ovens manufactured by General Electric have “Shabbat settings” that allow their use throughout Shabbat; a timer keeps the oven’s heat on low constantly. And some buildings now have Shabbos elevators, which continue to run automatically on Friday night and Saturday, stopping on every floor throughout that period.

The Kosher Switch is another development in the Orthodox world that claims to allow Jews an acceptable way to turn on and off lights during Shabbat.

“We humans are always going to figure out ways to beat the law,” said Miller.