vox

vox is a Rust-native RPC framework where Rust traits are the schema. There is no separate IDL, no code-generation pipeline to wire up: you define an async trait, annotate it with #[vox::service], and get a type-safe client and dispatcher that serializes with Facet. Implementations for TypeScript and Swift are generated from those same Rust definitions.

#[vox::service]
pub trait Calculator {
    async fn add(&self, a: i32, b: i32) -> i32;
    async fn divide(&self, a: i32, b: i32) -> Result<i32, MathError>;

    /// Client sends numbers, server returns the running sum.
    async fn sum(&self, numbers: Rx<i32>) -> i64;

    /// Server streams results back to the client.
    async fn generate(&self, count: u32, output: Tx<i32>);
}

Implementing a service

impl Calculator for MyCalculator {
    async fn add(&self, _cx: &Context, a: i32, b: i32) -> i32 {
        a + b
    }

    async fn divide(&self, _cx: &Context, a: i32, b: i32) -> Result<i32, MathError> {
        if b == 0 { Err(MathError::DivisionByZero) } else { Ok(a / b) }
    }

    async fn sum(&self, _cx: &Context, mut numbers: Rx<i32>) -> i64 {
        let mut total = 0i64;
        while let Some(n) = numbers.recv().await.ok().flatten() {
            total += n as i64;
        }
        total
    }
    // ...
}

Using a client

let client = CalculatorClient::new(connection_handle);

let result = client.add(2, 3).await?;

match client.divide(10, 0).await? {
    Ok(r)  => println!("result: {r}"),
    Err(MathError::DivisionByZero) => println!("cannot divide by zero"),
}

Features

• Bidirectional RPC — request/response with correlation ids
• Channels — Tx<T> / Rx<T> with credit-based flow control
• Service lanes — multiple independently routed services on one connection
• Transport-agnostic — TCP, WebSocket, Unix sockets, and shared-memory hub
• Middleware — intercept requests for auth, tracing, rate-limiting, etc.
• OpenTelemetry — built-in distributed tracing via vox_telemetry

Language support

Language	Status
Rust	Reference implementation
TypeScript	Generated client/server
Swift	Generated client/server

Specification

See the spec for the formal protocol definition.

License

Licensed under either of:

• Apache License, Version 2.0 (LICENSE-APACHE or http://www.apache.org/licenses/LICENSE-2.0)
• MIT license (LICENSE-MIT or http://opensource.org/licenses/MIT)

at your option.