Number masking and IVR are two phone services that apps and companies use for calls. Number masking connects two people by phone without showing either of them the other's real number. IVR, short for interactive voice response, is the recorded phone menu that says "press 1 for…" and acts on the key you press.
Delivery and taxi apps in India use number masking on almost every order. The customer does not want a stranger to keep her number. The rider's number should stay private too. And the app wants a record of every call in its own system.
Here is a typical case. A grocery rider in Visakhapatnam reaches a large apartment complex and cannot find tower C. He taps "Call customer" in his app. His phone dials a virtual number, a phone number that belongs to the masking service and not to any person. The service receives the call. Through an API, it asks the grocery app which order this rider is delivering now. An API is a fixed format in which one program asks another for information. The app replies with the customer's real number. The service then calls the customer and joins the two calls together. The customer's phone shows the virtual number, not the rider's. When the order is marked delivered, the app ends the link. If the rider calls the same virtual number later, the call no longer reaches the customer.
One virtual number can serve many orders at once. For each incoming call, the service checks which phone is calling and which order that phone is linked to right now. Then it decides whom to connect.
IVR handles a different moment: when a customer calls the company. Say a customer calls the grocery company's helpline. The IVR plays "Press 1 for an order you placed today. Press 2 for a refund." She presses 1. The IVR finds her latest order from her phone number and reads out its status. If she still needs help, it passes the call to a person in the contact centre. Newer menus understand a whole spoken sentence instead of key presses. This is called conversational IVR. Some calls are answered completely by voice bots.
Both services carry calls as data, using VoIP, until the call reaches the mobile operator's network. They are often sold by the same companies that sell messaging and voice APIs. In India, a few companies built these services first for consumer apps, and many apps still use them. Before a new menu goes live, a company can test every branch of it with contact centre testing, which places automatic test calls.