Generating, from transactions performed at a production computing system, information that can be used to effectively test new, updated, and/or modified source code to be deployed within the production computing system. In one example, this disclosure describes a method that includes communicating with a production processing system to determine an initial state of the production processing system; capturing information about a plurality of transactions executing across a plurality of application servers included within the production processing system; communicating with a test processing system to deploy source code within the test processing system that is not included in the production processing system; generating a replay test script; and communicating with the test processing system to enable the test processing system to execute the replay test script.