我在 Twilio 的工作，所以我回答这个问题很多。运营商收取发送消息。总要有人付出代价。 ，做本土传递的每个SMS网关传递该费用。另一种选择是通过电子邮件发送。它是免费的，但也有权衡。你要知道哪个运营商的收件人使用，而且他们有，如果它的变化来通知您。交货也是不可靠。

I work at Twilio, so I answer this question a lot. Carriers charge to send messages. Someone has to pay for it. Every SMS gateway that does native delivery passes on that fee. Your other option is sending via email. It's free, but there are trade-offs. You have to know which carrier the recipient uses, and they have to notify you if it changes. Delivery is also not as reliable.