CTCI (Computer-to-computer interface) is a digital communications protocol that allows customers of the NASDAQ (National Association of Securities Dealers Automated Quotations) to conduct business in the options market. CTCI is based on the same technology as the Common Message Switch (CMS) gateway, the standard interface used among stock and options traders.
The CTCI protocol facilitates order entry, confirmation, modification, cancellation and rejection. Trade reporting messages include order status reports, execution reports, updates and corrections. When CTCI is implemented, it is not necessary for the subscriber to use a NASDAQ workstation. CTCI supports IBM WebSphere message queue middleware to facilitate enterprise application integration (EAI), which allows the use of diverse architectures and operating systems in the trading environment.