Requirements¶
| Requirement | Version |
|---|---|
| Rust | >= 1.91 |
| UniFFI | = 0.32.0 |
| Gradle | >= 9.6.1 |
| Kotlin | >= 2.4.0 |
| Android Gradle Plugin | 9.x, only if you build for Android |
| JDK | 17 |
The UniFFI version must match exactly. The generated Kotlin depends on the FFI layout of a specific UniFFI release. On JVM and Android the bindings check the version when the library is first loaded (see Troubleshooting).
The project itself is built and tested with Rust 1.97.1, Gradle 9.7.0, Kotlin 2.4.0 and AGP
9.3.1.
Don't use a custom global allocator¶
Warning
Your crates must use Rust's default allocator. Don't set a #[global_allocator] (for example
mimalloc or jemalloc) in any crate that is built with this plugin, or in its dependencies.
Buffers that Kotlin sends to Rust are allocated by the UniFFI runtime's library, and freed by your crate. That only works when both use the same allocator, which is the system allocator by default. With a custom allocator, freeing such a buffer corrupts memory or crashes the process. See Runtime for details.
Toolchain¶
- Rust via rustup. The plugin calls
cargoandrustup, fromPATHor from~/.cargo/bin. If a Rust target is missing, the plugin runsrustup target addfor you. - Android NDK, for Android targets. See Targets.
- Xcode command line tools, for Apple targets. Apple targets can only be built on macOS.
- Cross toolchains if you build release JVM artifacts for other desktop platforms. See Targets.