It's dubbed Tinder for teens, and now one police department is warning parents to check their child's phone for the app.
Before the start of this school year, Rachel Honey bought her preteen son a cellphone to stay in touch.
Pierson Honey uses it to play games, music, and Snapchat with his friends.
"It's one of the safest because you can choose who your friends are and who looks at what you're posting," Pierson Honey said.
But there's an app called Yellow that connects to Snapchat.
There are reportedly 7 million Yellow users worldwide.
It's being described as "Tinder for teens," where you swipe left and swipe right.
"I think it's terrible. I think it's already so hard to get parental controls on your phone and this is just one more thing that makes it scary as a parent," Rachel Honey said.
The app that’s filled with emoji is now attracting the attention of law enforcement.
"Because there is no verification about a person’s age, and an adult can create an app and pose as a 13, 14-year-old and with location settings find teenagers in close proximity to them," Master Police Officer Danny Chavez, a spokesperson with the Lenexa, Kansas, Police Department, said.
Lenexa police wrote about the app on Facebook to alert parents about potential dangers.
Besides choosing who to like or not, Yellow users can also swap photos.
"There have been individuals who have shared inappropriate pictures with each other that would constitute as child pornography," Chavez said.
Laura Chambers tries her best to keep a close eye on her daughter’s phone. Abby, 12, doesn't even use Snapchat.
"You feel like you kind of get separated from your friends that you use that stuff like drama and everything," Abby Chambers said.
"It's our job to keep our kids safe, whether it's on the street or on the Internet, so no it wouldn't be in my house at all," Laura Chambers said.