WebAssembly, also known as Wasm, is a binary format for representing executable code, designed to be easily embeddable into other projects. It's also a perfect candidate for a user-defined functions (UDFs) back-end due to its ease of integration, performance and popularity. ScyllaDB already supports user-defined functions expressed in WebAssembly in experimental mode, based on an open-source runtime written natively in Rust - Wasmtime. This talk will cover a few examples of how to create Wasm functions in ScyllaDB, how to combine them into powerful user-defined aggregates and what are the future plans of integrating with Wasmtime and Rust even further. To watch all of the recordings hosted during Scylla Summit 2022 visit our website here: https://www.scylladb.com/summit.