A method, apparatus, and computer instructions for programmatically generating synthetic transactions to monitor performance and availability of a Web application. The mechanism of the present invention may be implemented as a Java 2 Platform Enterprise Edition (J2EE) transaction, wherein the J2EE application is instrumented with just-in-time-instrumentation (JITI). A JITI probe determines if a customer request object contains a cookie. If not, the JITI probe inserts a cookie into the response object. The cookie is used to track URIs visited by the customer. An algorithm is used to identify the baseline customer transaction path based on the URIs in the cookie. All baseline customer transaction paths for all customers are then correlated to form a unique transaction, wherein the unique transaction comprises the most common tasks performed in the Web application. The Web application may then be monitored by programmatically recording and scheduling playback of the unique transaction.