A method for detecting unreliable response conditions in a plurality of back-end transaction processing systems also can include the steps of: reading a list of references to a plurality of subscribing e-commerce systems; generating and dispatching placebo transactions to each e-commerce system in the list; receiving responses to the dispatched placebo transactions; computing transaction latency data based upon when each placebo transaction is dispatched to a subscribing e-commerce system, and when a corresponding response is received; and, notifying individual subscribing e-commerce systems when computed transaction latency data for the individual subscribing e-commerce systems indicates an unreliable response condition in an associated back-end transaction processing system.