His Parkland classmates became activists. He created a wellness app.

Kai Koerber was a junior at Marjory Stoneman Douglas High School when a gunman killed 14 students and three staff members there on Valentine’s Day in 2018. When he saw his peers – and himself – struggling to get back to normal, he wanted to do something to help people save their lives. their emotions on their own terms.

While some of his classmates at the school in Parkland, Florida, have worked to advocate for gun control, entered politics or simply taken a step back to heal and focus on their studies, Mr. Koerber’s background was in technology – he originally wanted to be a rocket scientist – led him in a different direction: building a smartphone app.

The result was Joy, which uses artificial intelligence to suggest bite-sized mindfulness activities for people based on how they’re feeling. The algorithm that Mr. Koerber’s team built is designed to recognize how someone is feeling from their voice – regardless of the words or language they speak.