[gusz]

I have Android Oreo 8.0 on a Galaxy S9, and I get the pink message notification at the right side of my screen shown in the attached photo when I receive a text message. But the phone has at least three messaging apps installed: Facebook Messenger, Android Messages, Samsung Messages, maybe T-Mobile, who knows? I'm confused as to which app is default, which provides the pink notification and, worse yet, that I suspect I'm losing messages in the confusion.

So, which app provides the pink notification in the photo, or does receipt on *any or all* of the messaging apps trigger the notification?

I note that I use multiple platforms in my work: Linux, Windows, MacOS, IOS and Android. Which text messaging app is best to support all these platforms?

Thx, Gus

[SpookDroid]

That looks like Google's Messages, but once you open it you should be able to tell easily from the menu button. Also, for texting, only one app can be default, so whenever you open any of them from your app launcher, if it's NOT the default, it'll ask you if you want to make it the default. Only that app can send texts, and in some cases, only read some messages (you're not missing any, they're all being received, only the default app would be able to notify).

Since Google's Messages offers texting over any web browser, it would be the best option for you if you use multiple platforms. I also recommend Pulse (but that's a paid app to add that feature) because Messages, for me, it's waaaaay too bare bones.

You can also find out which app is the default texting app by searching for DEFAULT APPS in the phone's Settings (or going to the Apps/Default Apps section of your phone's settings). There, whatever shows in the 'Messaging App' section is the current default app. Again, only that app is allowed full access to your SMS/MMS database and only that app can send messages, which is why, for instance, if you want to use Pulse's or Message's web-based interface (or other apps in the case of Pulse), it MUST be set as the default app on your phone or it won't work.

[gusz]

SpookDroid: That's a great answer - I appreciate your help!