I just recently discovered that in many cases, it's really feasible to get a phone number on the spot.

Like when I previously registered for overseas websites, tested SMS verification code interfaces, or did account experiments, buying a new SIM card was obviously not practical.
Later, I found out about SMS receiving platforms—these are incredibly convenient, providing virtual numbers to receive SMS verification codes.

I've also encountered quite a few pitfalls myself—some platforms simply don't receive messages, others have delays of half a day, and only after experimenting did I figure out which ones are reliable.
In summary, SMS-Activate and 5SIM perform the best overall, with verification codes arriving within about 10 seconds, and they cover many countries.
Super Cloud SMS is well-optimized for US and Chinese number ranges—US numbers get responses in 10–30 seconds, Chinese numbers within 5–20 seconds.
Xiaoniao SMS is especially fast for domestic testing, usually visible within 5–15 seconds, and offers good value.
Getsmscode is cheap and suitable for light use.

Using SMS receiving platforms is actually very simple—after registering and topping up, select the country and application category, receive a virtual number, enter it on the target website, and the verification code will be displayed directly in the backend.
Some platforms also support API integration, suitable for bulk or automated needs.
But be aware—shared numbers are more likely to be flagged or blocked, and verification codes from less popular platforms may be delayed.
It's recommended to prepare 2–3 backup numbers to switch quickly if one becomes invalid.

Honestly, the main purpose of SMS receiving platforms is to protect privacy, prevent spam, or create secondary accounts.
Never use them for illegal activities; obeying the law is fundamental.
If you're just testing interfaces, any platform that supports API access will do.
But if you need stable registration on a specific overseas site, it's best to top up multiple numbers.
Some platforms support "one-click number switching," which is really practical and can prevent waste.