Navigating OTP Delivery Challenges with Virtual Numbers: Insights and Solutions


In the digital age, the security of online transactions and interactions has never been more paramount. One-Time Passwords (OTPs) have become a cornerstone of digital security, providing a layer of verification that’s both simple and robust. However, as the landscape of digital communication evolves, so too do the challenges associated with delivering these crucial security tokens. Virtual numbers, while offering flexibility and privacy, introduce complexities in OTP delivery due to their unique position in the telecommunications infrastructure.

Virtual Numbers and OTP Compatibility:

A Closer Look Virtual numbers offer users the ability to send and receive calls and messages through cloud-based platforms rather than traditional mobile networks. This flexibility makes them an appealing choice for businesses and individuals seeking enhanced privacy and control over their communications. AutoSender (Pro) app, a leading service in this domain, exemplifies the benefits of virtual numbers, providing users with up to five real US phone numbers for comprehensive messaging needs. However, the question arises: Can all OTPs be successfully received on virtual numbers like those provided by AutoSender? The answer lies in understanding the telecommunications framework and the criteria used by OTP issuers to determine message delivery eligibility.

The Telecommunications Framework:

PLMN, PSTN, and Virtual Numbers

Public Land Mobile Network (PLMN) vs. Public Switched Telephone Network (PSTN): PLMN encompasses mobile telecommunications technologies, storing user data and managing routing via network elements like the Home Location Register (HLR) or the Home Subscriber Server (HSS) for LTE networks. Conversely, PSTN is the traditional network for landline phones, relying on central office switches for call routing. Virtual numbers navigate these distinctions by adhering to the E.164 numbering scheme, ensuring global interoperability and the ability to integrate with both mobile and landline networks.

Short Code Support and E.164 Numbering: Short codes, crucial for sending bulk messages such as OTPs, require specific integration between the sender’s systems and the recipient’s mobile network. Virtual number providers must navigate these requirements, ensuring compatibility with mobile carriers’ systems to facilitate OTP delivery.

Identifying Virtual Numbers: OTP issuers, including Internet service providers, utilize databases that categorize numbers as mobile, landline, or VoIP. Before sending an OTP, a service might perform a carrier lookup to determine the number’s classification. If identified as VoIP or associated with a virtual number service, the OTP may not be sent due to security policies aimed at minimizing fraud risk. This process highlights a critical challenge in using virtual numbers for secure transactions: not all services treat virtual numbers the same, impacting the reliability of OTP reception.

AutoSender (Pro) app:

AutoSender stands as a prime example of how virtual numbers can be optimized for secure communications, including the reception of OTPs. By providing real US phone numbers and integrating with telecommunications networks, AutoSender navigates the complexities of OTP delivery. However, users may still encounter services that restrict OTPs to traditional mobile numbers, underscoring the importance of understanding the underlying telecommunications infrastructure and the criteria used by OTP issuers.


The interplay between virtual numbers, telecommunications standards, and digital security measures is intricate, with significant implications for the reliability of OTP delivery. As services like AutoSender continue to innovate in the space of virtual communications, users and OTP issuers alike must remain informed about the technical and security considerations influencing the landscape. Understanding these factors is crucial for ensuring that the digital world remains both accessible and secure.