As others have pointed out, this kind of automated business use is very much against the T&Cs of carriers, so if you do this heavily you can expect to run into issues.

They can and do detect this kind of thing. In a similar vein there is also a whole industry in "sim boxes". Effectively a box of SIM cards / radio equipment that acts as a server. These can similarly be set up as servers to send SMS through carriers ( https://en.wikipedia.org/wiki/SIM_box ), though seemingly the popular use is to bridge VOIP calls to local destinations and sell "minutes" to others. There is also apparently a whole industry in software to manage them. These days that management software allegedly includes measures to have the SIMs behave like humans to evade detection (the sims text each other, browse around, sleep for hours of the day, and so on).

Easier to just use a usb/minipcie modem and operate directly from the 'server' - no batteries, no OS to crash, no nothing, simple AT commands on linux "middleware" (modemmanager etc.)

There are so many interesting things that can be done with an Android phone. Tomorrow, if the Google Play store decides not to publish this app, I can still install it via the APK file. I wonder how many of these apps will be usable after Google's new rules about sideloading.

I've done this on symbian phone many many moons ago, for sms and mms messages. We all been there :)

definitely a great setup for development, tho probably a good idea to have the Twilio integration ready to go.

legitimate messages or not, this will look like spam if you get a surprise burst of traffic. and providers will nuke your SIM, maybe blacklist your phone's IMEI, if they suspect you're using it for spam.

also is it weird that "That's its whole life now." made feel a bit sorry for the phone? might be spending too much time in opencode...

I can feel the 10DLC violations in the US already running through my blood. You will be eviscerated by the carriers for doing this for anything longer than a single day.

I hope your disaster recovery (or 'didn't realize') strategy includes a drawer full of additional burner Android phones and SIM cards.

Unlimited texts.

Nope. Sorry, it is unlimited texts for *personal* use --- as defined by the carrier.

Send "too many" and your account can be suspended.

Some carriers offer an email to SMS gateway so if you can send email, you can skip the $20 Android phone.

https://20somethingfinance.com/how-to-send-text-messages-sms...

Maybe next he'll learn about sim900 and derivatives.

$20 and full android stack seems a massive waste for this, nevermind unreliable.