Create a project
Start from the duckfn extension template or DuckDB's official Rust extension template, write with duckfn and quack-rs, and build with the official extension-ci-tools makefiles.
Project structure
The one rule an extension project follows â every crate root declares the same extension module â and the two errors you get when you break it.
Installation
Add duckfn to a crate, declare the cdylib crate type, and why a local DuckDB build is not needed.
Quick start
Write, build and load a minimal duckfn extension, then call it from SQL.