Methods, systems, and articles of manufacture for program integration are provided herein. A method includes identifying each varying portion of a customized version of a program as compared to a standard version of the program; identifying each common portion of the customized version as compared to the standard version; merging the customized version with the standard version to create a merged version of the program based on the identified common portions and the identified varying portions such that semantics of both the customized version and the standard version are preserved in the merged program; associating each change contributed by the customized version, represented by the varying portions in the merged version, to a defined extension point in the merged version; and generating a program extension for the standard version for each span of the program contained in a defined extension point span in the merged version.