usesend-rs

Rust SDK for useSend — an open-source Resend alternative.

Installation

[dependencies]
usesend = "0.1"
tokio = { version = "1", features = ["macros", "rt-multi-thread"] }

Quick Start

use usesend::types::email::SendEmailRequest;

#[tokio::main]
async fn main() -> usesend::ApiResult<()> {
    let client = usesend::UseSend::new("us_api_key");

    let email = SendEmailRequest::builder()
        .from("hello@example.com")
        .to("user@example.com")
        .subject("Hello from useSend!")
        .html("<h1>Welcome!</h1>")
        .build();

    let resp = client.emails.send(&email).await?;
    println!("Sent: {}", resp.email_id);
    Ok(())
}

Features

• Builder pattern — Fluent API for composing emails, contacts, campaigns, and more
• Sub-service architecture — Organized access via client.emails, client.domains, client.contacts, etc.
• Rate limiting — Built-in governor-based rate limiter with automatic 429 retry
• Typed IDs — DomainId, EmailId, and other strongly-typed identifiers
• Self-hosted support — Point to your own useSend instance with UseSend::with_base_url()
• Environment variable — Read API key from USESEND_API_KEY via UseSend::from_env()

👉 Full usage guide → — Domains, Contacts, Campaigns, Feature Flags, and more.

Crate Structure

Crate	Description
usesend	High-level SDK with builder pattern — use this
usesend-api	Low-level typed HTTP client and request/response models

Most users should depend on usesend. Use usesend-api directly only if you need raw access to the API types or want to build your own abstraction layer.

Minimum Supported Rust Version

The MSRV is 1.88 (Rust edition 2024).

Contributing

Contributions are welcome! See CONTRIBUTING.md for guidelines.

License

Licensed under either of MIT or Apache-2.0 at your option.