TL;DR: Both iPhone and Android show a small colored dot or icon in the status bar when an app is actively using the microphone — if you see it appear when you're not on a call or using voice input, that's worth investigating. Check Settings > Privacy & Security > Microphone on iPhone or Settings > Privacy > Permission manager > Microphone on Android, revoke access from apps that don't need it, and pay attention to the microphone-use indicator going forward.
Both iPhone and Android show a small colored dot or icon in the status bar when an app is actively using the microphone — if you see it appear when you're not on a call or using voice input, that's worth investigating.
What Usually Causes This
Microphone access is usually granted during setup for a legitimate feature like voice search or video calling, but the permission then stays active for the app indefinitely unless manually revoked.
What to Do About It
Check Settings > Privacy & Security > Microphone on iPhone or Settings > Privacy > Permission manager > Microphone on Android, revoke access from apps that don't need it, and pay attention to the microphone-use indicator going forward.
If this looks similar to something else you've seen, it's worth reading How to Check Your Digital Footprint on a New Device.
This pattern shows up elsewhere too — see How to Tell If Your Email Was Used to Sign Into a New Device.
Frequently Asked Questions
What are the real warning signs?
Both iPhone and Android show a small colored dot or icon in the status bar when an app is actively using the microphone — if you see it appear when you're not on a call or using voice input, that's worth investigating.
What usually causes this?
Microphone access is usually granted during setup for a legitimate feature like voice search or video calling, but the permission then stays active for the app indefinitely unless manually revoked.
What should I do about it?
Check Settings > Privacy & Security > Microphone on iPhone or Settings > Privacy > Permission manager > Microphone on Android, revoke access from apps that don't need it, and pay attention to the microphone-use indicator going forward.
Should I be worried if I only see one sign?
One sign alone (like a slower device) is usually not cause for alarm — most single symptoms have mundane explanations. Multiple signs together, especially unexpected data usage or unfamiliar apps, are worth investigating.