Shim (computing)

Shim (computing)

In computer programming, a shim (from shim) or shiv is a small library that transparently intercepts an API and changes the parameters passed, handles the operation itself, or redirects the operation elsewhere. Shims typically come about when the behavior of an API changes, thereby causing compatibility issues for older applications which still rely on the older functionality. In such cases, the older API can still be supported by a thin compatibility layer on top of the newer code. Web polyfills are a related concept. Shims can also be used for running programs on different software platforms than they were developed for.