Methods, systems, and computer program products for preventing double processing of a repeated or duplicated booking request received from a client in a transaction session over a computer network. A first booking request is received from the client over the computer network and processed. When a second booking request repeating or duplicating the first booking request is received from the client, response data prepared in response to the first booking request is assigned to the repeated booking request. A response to the repeated booking request is returned to the client. The response includes the response data prepared in response to the first booking request.