Where can I find some hardware SMS gateways (GSM modems?)? SMSEagle's seem good, but I'm looking for something cheaper and without many bells and whistles.
@JMY1000 To send out many SMSs rapidly. I've seen things like SIM900A (which isn't LTE or 5G), but I need something that works with 4G LTE or 5G, preferably with an SMA antenna connection.
Geremia, using customer grade SIM may raise fraud alarm in mobile operator. Mass SMS servers usually are based on custom agreement. But you can check this, its 4G, a bit cheaper and support more than one SIM: ejointech.shop/products/…
Usually SMS usage is under fair usage policy (if you have no limit for SMSes you can send. Based on my previous experience with other mobile operators there is always such rule in operator antifraud systems :)
No, that's how fast the unit can manage and send SMS. But do not forget mobile operator (may) add throttle to the customer SMSes. And add them in SMSC in different queues (with different priority)