Rust
Detected from Cargo.toml. The newest published toolchain compiles the release binary.
See Buildpacksfor how detection and version policy work.
Detects
Cargo.toml in the base directory.
Versions
Default is Rust 1.96. Published toolchains as of September 2026 include 1.95-1.98. Rust on Nodion always uses the newest published toolchain. An older rust-version still builds.
The requested version is read from, in this order:
rust-toolchain.tomlchannel(numeric channels only;stable/nightlyfall through)rust-toolchainrust-versioninCargo.toml
The toolchain is not shipped in the run image. Only your binaries are.
Install and build
cargo build --release. With a Cargo.lock, the build is --locked.
Start command
Default web is the binary that matches the Cargo package name, then server, api, web, or app, otherwise the first executable in target/release. Extra binaries become extra process types. Override with a Procfile. Listen on PORT.