It's called "My School Alert."
It was developed by a middle school nurse in Dothan, Alabama.
The app helps school employees stay in touch during a lockdown and helps administrators get important information such as how many kids are accounted for and who needs help.
The app's developer, Janice Horne, says she hopes the technology will be a reassuring tool for school staff.
"Even the drills are scary because it's the unknown, you have no idea what's going on outside those doors and then everyone has to be quiet, so then your mind just wonders what's going on - is it real is it not real," Horne says.
So far, the app is being used in schools in three Alabama cities.
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