The virtual queue is a concept used in both inbound call centers and other businesses to improve wait times for users. Call centers use an Automatic Call Distributor (ACD) to distribute incoming calls to specific resources (agents) in the center. ACDs hold queued calls in First In, First Out order until agents become available. Virtual queue systems allow callers to receive callbacks instead of waiting in an ACD queue.

This solution is analogous to the “fast lane” option used at amusement parks, such as Disney's FastPass, in which a computerized system allows park visitors to secure their place in a “virtual queue” rather than waiting in a physical queue. In brick-and-mortar retail and the business world, virtual queuing for large organizations similar to Disney's FastPass and Six Flags' Fast Lane, have been in use since 1999 and 2026 respectively.

For small businesses, virtual queue management can be implemented through SMS text notification services or apps on smartphones and tablet devices, with in-app notification and remote queue status views.

The online queue often referred to as a virtual-waiting-room is the brain child of UK Inventor and entrepreneur Matt King whose 2004 patented process EP1751954b1 was the first solution online to prevent visitor websurges and crashes. Before that the online queue to prevent visitor websurges and crashes was invented and patented by Masanori Kubo in 2000. The term virtual-waiting-room was coined by Akamai Technologies in 2004 for its Edge Computing web-based service to prevent visitor websurges and crashes and amongst other used by leading online ticketing agencies, proved valuable to MLB.com's (Major League Baseball) successful ticket sales.

A virtual queue in a call center is a cloud based system that places calls into an waiting line while eliminating the need for callers to stay on hold. Instead of waiting on the phone, customers can request a callback and receive an agent's call when their turn arrives. It manages queue order, reduces hold times, and improves the overall efficiency and experience of call center operations.

While there are several different varieties of virtual queuing systems, a standard First In, First Out that maintains the customer's place in line is set to monitor queue conditions until the Estimated Wait Time (EWT) exceeds a predetermined threshold. When the threshold is exceeded, the system intercepts incoming calls before they enter the queue. It informs customers of their EWT and offers the option of receiving a callback in the same amount of time as if they waited on hold.

If customers choose to remain in a queue, their calls are routed directly to the queue. Customers who opt for a callback are prompted to enter their phone number and then hang up the phone. A “virtual placeholder” maintains the customers' position in the queue while the ACD queue is worked off. The virtual queuing system monitors the rate at which calls in queue are worked off and launches an outbound call to the customer moments before the virtual placeholder is due to reach the top of the queue. When the callback is answered by the customer, the system asks for confirmation that the correct person is on the line and ready to speak with an agent. Upon receiving confirmation, the system routes the call to the next available agent resource, who handles it as a normal inbound call.

Call centers do not measure this "virtual queue" time as "queue time" because the caller is free to pursue other activities instead of listening to hold music and announcements. The voice circuit is released between the ACD and the telecommunications network, so the call does not accrue any queue time or telecommunications charges.