UniFFI — Rust ↔ Kotlin/Swift Bindings

UniFFI by Mozilla — generates idiomatic Kotlin, Swift, Python, and Ruby bindings from a Rust crate. Covers UDL definition, proc-macro mode, async support, callback interfaces, error handling, custom types, and the Kotlin Multiplatform fork (uniffi-kotlin-multiplatform-bindings) used by BDK, Breez SDK, CDK, LWK. USE WHEN: user mentions "UniFFI", "Rust to Kotlin", "Rust to Swift", "FFI bindings", "uniffi-rs", "UDL file", "uniffi-bindgen", "BDK bindings", "Breez SDK bindings", "kotlin-multiplatform-bindings", "Mozilla UniFFI" DO NOT USE FOR: Raw C FFI - use `languages/swift` interop quick-ref + Rust core DO NOT USE FOR: WebAssembly bindings - use wasm-bindgen DO NOT USE FO…