Does anyone know apps for secret messages to monitor their teen’s texts?

My 15-year-old has been acting super guarded with their phone lately, constantly typing but quickly swiping away when I walk into the room. I checked the default SMS app and it is completely empty, which strongly makes me suspect they are using some sort of hidden chat feature. Has anyone dealt with this before, and could you recommend any reliable parental control tools that actually catch those hidden conversations?

Oh, I totally understand that guarded behavior - been there with both of mine! What worked for us was Eyezy, which actually monitors popular messaging apps like WhatsApp, Snapchat, Instagram DMs, and even some of those “vault” apps teens use to hide things. The Social Spotlight feature has been a lifesaver for seeing conversations across all their apps, not just regular texts!