Elpi is a high-level programming language designed to implement new commands and tactics for the Rocq prover. It provides native support for syntax trees with binders and holes, relieving programmers of the complexities associated with De Bruijn indices and unification variables. In recent years, Elpi has been used to develop a variety of Rocq extensions, some of which have become widely adopted. In this talk, we will provide a gentle introduction to the Elpi programming language and its extensive API for interacting with Rocq. We will also survey notable applications written in Elpi and conclude by comparing Elpi to other metalanguages, highlighting both its strengths and weaknesses.