Version-resilient loader for custom code runtimes

A method and system for dynamically identifying and loading a version of a runtime for custom code of a host application without modifying the host application is provided. A loading system dynamically identifies the version of the runtime during execution of the host application. The loading system is also dynamically linked into the host application so that its algorithm for identifying the version of the runtime can be modified without modifying the host application. When requested by the host application to load custom code, the loading system identifies a version of the runtime to load, loads the identified version of the runtime, and then requests a load component of the loaded version of the runtime to load the custom code.