Build safe, intelligent systems with Sailfin

A systems-friendly programming language with effect types, capability-based security, and native compilation via LLVM.

curl -fsSL https://raw.githubusercontent.com/SailfinIO/sailfin/main/install.sh | bash
server.sfn
struct Config {
    host: string,
    port: number,
    verbose: bool,
}

fn load_config(path: string) -> Config ![io] {
    let raw = fs.read(path);
    return Config.parse(raw);
}

fn handle(req: http.Request) -> http.Response ![net] {
    return http.Response {
        status: 200,
        body: "Sailfin is running",
    };
}

fn main() ![io, net] {
    let config = load_config("app.toml");
    print("Listening on " + config.host);
    serve(handle, { port: config.port });
}

Built for

Systems Programming

Native compilation via LLVM and a self-hosted toolchain make Sailfin suitable for performance-critical infrastructure.

Capability-Controlled Services

The effect system checks that IO, network, and other capabilities are declared at compile time — catching direct violations before runtime.

CLI Tools & Automation

Concise syntax, fast compilation, and single-binary output make Sailfin ideal for developer tooling.

Safe Concurrent Systems

Effect tracking helps you build reliable services today, with structured concurrency planned to make capability boundaries even more explicit and auditable.

Ready to dive in?

Install Sailfin and build your first program in minutes.