On iOS you won’t find a “real” Snapchat-spy app unless you’re willing to jailbreak (which I don’t recommend—voids warranties, breaks updates, undermines all that Apple privacy & reliability is built on). Instead, use native Screen Time + Family Sharing:
- Set “Downtime” for Snapchat or App Limits so you know when it’s being used
- Enable “Ask to Buy” for any app installs
- Check weekly Screen Time reports for total Snapchat use
If you just need alerts on risky language or sudden spikes, consider Bark or Qustodio—they won’t show every snap, but you’ll get keyword flags and usage summaries without jailbreaking.
On Android you can root and install mSpy or similar, but it’s a security headache and often unstable. Better to lean on iOS’s locked-down parental controls and open conversation.