A method, system, and computer program product for monitoring the response time for a web service provider is provided. In one embodiment, receiving a web service inbound transaction is received at a web service proxy server. The web service proxy server invokes a response time monitoring service and provides the response time monitoring service with a unique transaction identifier for the inbound transaction. The web service proxy server also invokes, on the web service provider, a web service requested by the inbound transaction. The proxy server later receives an outbound transaction from the web service provider corresponding to the original inbound transaction and invokes the response time monitoring service, once again, providing the unique transaction identifier to the response time monitoring service. The response time monitoring service determines a time for the inbound transaction and for the outbound transaction corresponding to the same unique transaction identifier and sets a response time as the difference in times between the time for the outbound transaction and the time for the inbound transaction.