reqx

HTTP transport for Rust API SDKs. reqx provides consistent retry, timeout, idempotency, proxy, TLS, streaming, and observability behavior across async and blocking clients.

Features

Idempotency-aware retries with Retry-After, retry budgets, and circuit breakers
Per-attempt, response-body, connect, and total timeouts
Async and blocking clients with buffered and streaming I/O
Rate limiting, concurrency limits, and multi-endpoint routing
Rustls or native-tls, including custom CAs and mTLS
Proxies, redirects, response size limits, and structured errors
Metrics, observers, interceptors, and optional OpenTelemetry integration

Installation

The default build uses the async client with rustls (ring) and enables gzip response decoding:

cargo add reqx

To replace the default transport or TLS backend:

cargo add reqx --no-default-features --features async-tls-native,compression-gzip

Feature	Transport
`async-tls-rustls-ring`	Async, rustls with `ring` (default)
`async-tls-rustls-aws-lc-rs`	Async, rustls with AWS-LC
`async-tls-native`	Async, platform-native TLS
`blocking-tls-rustls-ring`	Blocking (`ureq`), rustls with `ring`
`blocking-tls-rustls-aws-lc-rs`	Blocking (`ureq`), rustls with AWS-LC
`blocking-tls-native`	Blocking (`ureq`), platform-native TLS

TLS backend features are additive. When several are enabled, select one with Client::builder(...).tls_backend(...); rustls with ring is preferred by default. Optional capabilities include all-codec compression, individual compression-* codecs, resumable-upload, and otel; enable otel before calling .otel_enabled(true).

Quick start

use std::time::Duration;

use reqx::prelude::Client;

async fn fetch_item() -> reqx::Result<()> {
    let client = Client::builder("https://api.example.com")
        .client_name("example-sdk")
        .request_timeout(Duration::from_secs(3))
        .total_timeout(Duration::from_secs(8))
        .build()?;

    let response = client.get("/v1/items/42").send().await?;

    println!("status={} bytes={}", response.status(), response.body().len());
    Ok(())
}

POST requests are retried only when they can be sent safely; provide an idempotency key when the API supports one.

Documentation

Run the async example with cargo run --example basic_json. For the blocking client, run:

cargo run --example blocking_basic --no-default-features --features blocking-tls-rustls-ring

License