Why people verify Truecaller with a separate number
A caller ID app works by matching phone numbers to names. When you register, the number you verify becomes your Truecaller profile, and you may be asked for a name and other details to go with it.
Some people want the spam blocking and caller ID without tying their personal number to a profile in another app. Verifying with a separate number lets you try Truecaller first and decide later whether you want your real number in it.
Note that verifying a different number does not decide how your personal number appears to other Truecaller users. That is a separate question; Truecaller explains its own options for managing how a number is listed.
How Truecaller verification works
Truecaller checks that you control the number you enter. Depending on your device and region, it may try an automatic check, or send a short SMS with a numeric code. If you are using a number that is not the SIM in your phone, pick the SMS option and type the code by hand.
ASMS.ai numbers receive SMS. If Truecaller offers a choice, choose the text message rather than a call.
The code is usually a few digits with a reminder not to share it. It expires quickly, so type it in as soon as it appears in your ASMS.ai inbox.
Truecaller verification code not arriving
Check the country code first. Truecaller asks for your country, and it must match the number: +1 for a US number, +44 for a UK one.
Second, the app may wait before letting you request another code. Let the timer run out instead of restarting the app repeatedly.
Third, if Truecaller declines the number, use the ladder: VoIP High Quality from $0.50, refunded if no code arrives, then a real UK number, then a private non-VoIP rental. Some caller ID apps are stricter with internet numbers, and a non-VoIP line is more likely to be treated like an ordinary mobile.
After you verify
Once Truecaller is set up, the verified number shows as yours inside the app. If you used a per-code number, it is only for that one code, so do not rely on it for anything later, such as moving the account to a new phone.
Your personal phone keeps working as normal, with its own SIM, calls and texts. Truecaller's caller ID and spam labels run in the app on that phone, while the account behind them is registered to the separate number you verified.
Per-code number or rental
If you only want to try the app, a per-code number is enough. It receives one Truecaller OTP and you are done.
If you plan to keep using the Truecaller account, rent a number. Reinstalling the app or moving to a new phone may mean verifying again, and the code must reach a number you still control. A rental stays yours for the period you choose, with unlimited SMS.
Free shared numbers are a poor fit here. They are public and often already registered on popular apps, so Truecaller may refuse them, and anyone could read the code.
Step by step
Sign in to ASMS.ai and add wallet balance. On the OTP page, choose Truecaller and the US pool, check the price and stock, and pay.
In Truecaller, pick the matching country, enter the number, and choose the SMS option. Copy the code from your ASMS.ai inbox into the app. For a profile you keep, rent the number on the Numbers page instead.