#api #client #io #network #serialization

no-std lucia

A flexible client API framework as well as a set of API collections

5 releases (breaking)

0.5.0 Dec 19, 2022
0.4.0 Nov 28, 2022
0.3.0 Aug 1, 2022
0.2.0 Jul 17, 2022
0.1.0 Jul 4, 2022

#1616 in Network programming

22 downloads per month
Used in lucia-apis

MIT license



CI crates.io Documentation License Rustc

A flexible client API framework for writing asynchronous, fast, organizable, scalable and maintainable applications with the Rust programming language. Supports several data formats, transports and custom parameters.

Checkout the lucia-apis project to see a collection of APIs based on lucia.


A structure that implements the Package trait describes request data as well as any other additional parameters like HTTP header values.

Auxiliary elements attached to the instance of an API like byte buffers or throttling parameters are declared in a separate mandatory entity called PkgsAux, which is responsible for assisting the creation and management of packages and their requests.

Take a look at the following example using lucia_macros to create a JSON-RPC request with fluent interfaces, reqwest to send data and serde_json to decode the returned bytes from the server.

use lucia::{dnsn::SerdeJson, network::{transport::Transport, HttpParams}};


pub struct MyApi;

type MyApiPackagesAux = PkgsAux<MyApi, SerdeJson, HttpParams>;

#[lucia::pkg(api(super::MyApi), data_format(json_rpc("my_endpoint")), transport(http))]
mod my_endpoint {
  impl super::MyApiPackagesAux {}

  #[derive(Debug, serde::Serialize)]
  pub struct MyEndpointReq<'any> {
    pub foo: i64,
    pub bar: &'any str,

  #[derive(Debug, serde::Deserialize)]
  pub struct MyEndpointRes {
    pub data: i32,

pub async fn fetch_my_endpoint() -> lucia::Result<i32> {
  let pkgs_aux = &mut MyApiPackagesAux::from_minimum(

  let pkg = &mut pkgs_aux.my_endpoint().data(123, "321").build();

  let trans = &mut reqwest::Client::new();

  Ok(trans.send_retrieve_and_decode_contained(pkg, pkgs_aux).await?.result?.data)

Data formats

Each request has one or more data formats attached specifically to an API.

They are what will be serialized and deserialized so in order to create yet another data format, it is necessary to implement Deserialize and Serialize according to the desired serializer.

Name URL
Borsh https://borsh.io/
GraphQL https://spec.graphql.org/
JSON https://www.json.org/json-en.html
JSON-RPC 2.0 https://www.jsonrpc.org/
Protobuf https://developers.google.com/protocol-buffers
XML https://www.w3.org/TR/xml/
YAML https://yaml.org/spec/


Can be applied to one or more different data formats.

Feature URL
borsh https://docs.rs/borsh
miniserde https://docs.rs/miniserde
rkyv https://docs.rs/rkyv
rust-protobuf https://docs.rs/protobuf
serde_json https://docs.rs/serde_json
serde-xml-rs https://docs.rs/serde-xml-rs
serde-yaml https://docs.rs/serde_yaml
simd-json https://docs.rs/simd-json


How a request should be deployed. Transports have their own trait conveniently called Transport.

Custom transport implementations can be declared in lucia-macros using the transport(custom(SomeTransport)) attribute.

Name Feature URL
Reqwest reqwest https://docs.rs/reqwest
Surf surf https://docs.rs/surf
TcpStream std https://doc.rust-lang.org/std/net/struct.TcpStream.html
tokio-tungstenite tokio-tungstenite https://docs.rs/tokio-tungstenite
UdpStream std https://doc.rust-lang.org/std/net/struct.UdpSocket.html


~229K SLoC