simple_smtp_sender

A Simple SMTP Email sender crate with the support of sync or async sending. Can be called from Python. Powered by powered by Rust, lettre and PyO3.

Overview

This project provides rust crate and a Python extension module implemented in Rust for sending emails via SMTP, including support for attachments, CC, and BCC. There are methods for both synchronous and asynchronous sending. It leverages the performance and safety of Rust, exposes a convenient Python API, and is built using PyO3 and lettre. The python module is compatible with Python 3.10 and above.

Features

Send emails via SMTP synchronously or asynchronously
Support HTML email contents
Attach files to emails
Support for CC and BCC
Secure authentication
Easy configuration via Python class
Flexible feature flags for Rust-only or Python-enabled builds
No Python dependencies required for Rust-only usage

Installation

Python Package from PyPI

uv pip install simple_smtp_sender
# or
pip install simple_smtp_sender

Rust Crate

Add to your Cargo.toml:

[dependencies]
# Default: includes Python bindings (requires Python environment)
simple_smtp_sender = "0.2.4"

# Rust-only version (no Python dependencies)
simple_smtp_sender = { version = "0.2.4", default-features = false, features = ["rslib"] }

Build from Source (requires Rust toolchain and maturin)

git clone https://github.com/guangyu-he/simple_smtp_sender.git
cd simple_smtp_sender
# prepare venv and maturin if needed
maturin develop

Or build a wheel:

maturin build
pip install target/wheels/simple_smtp_sender-*.whl

Requirements

Python >= 3.10 (for Python package)
Rust toolchain (for building from source)

Usage

An example test from Rust crate:

Note: this test can only be run natively if you installed with default-features = false, features = ["rslib"]

use simple_smtp_sender::{send_email_async, send_email_sync, EmailConfig};

#[test]
fn send_email_sync_test() {
    let config = EmailConfig::new(
        "smtp.example.com",
        "your@email.com",
        "your_username",
        "your_password",
    );
    let result = send_email_sync(config, vec!["recipient@email.com".to_string()], "Test Email", "Hello from Rust!", None, None, None);
    assert!(result.is_ok());
}

#[tokio::test]
fn send_email_async_test() {
    let config = EmailConfig::new(
        "smtp.example.com",
        "your@email.com",
        "your_username",
        "your_password",
    );
    let result = send_email_async(config, vec!["recipient@email.com".to_string()], "Test Email", "Hello from Rust!", None, None, None).await;
    assert!(result.is_ok());
}

//new builder method
#[test]
fn send_email_sync_builder_test() {
    let config = EmailConfig::new(
        "smtp.example.com",
        "your@email.com",
        "your_username",
        "your_password",
    );
    let result = config
        .send_to(vec!["recipient@email.com".to_string()])
        .subject("Test Email Builder")
        .body("Hello from Rust Email Builder!")
        .send();
    assert!(result.is_ok());
}

If you installed the Python feature (default), you can test the above codes using for example:

cargo test --no-default-features --features="rslib" send_email_sync_test

An example from Python API:

from simple_smtp_sender import EmailConfig, send_email, async_send_email

config = EmailConfig(
    server="smtp.example.com",
    sender_email="your@email.com",
    username="your_username",
    password="your_password",
)

# Synchronous send (blocking)
send_email(
    config,
    recipient=["recipient@email.com"],
    subject="Test Email",
    body="Hello from Rust!",
)

# With attachment, CC, and BCC:
send_email(
    config,
    recipient=["recipient@email.com"],
    subject="With Attachment",
    body="See attached file.",
    cc=["cc@email.com"],
    bcc=["bcc@email.com"],
    attachment="/path/to/file.pdf",
)

# Asynchronous send (non-blocking)
import asyncio


async def main():
    await async_send_email(
        config,
        recipient=["recipient@email.com"],
        subject="Async Email",
        body="Sent asynchronously!",
    )


asyncio.run(main())

API

`EmailConfig`

Configuration class for SMTP server and credentials.

server: SMTP server URL
sender_email: Sender's email address
username: SMTP username
password: SMTP password

`send_email(config, recipient, subject, body, cc=None, bcc=None, attachment=None)`

Sends an email synchronously (blocking) using the provided configuration.

config: EmailConfig instance
recipient: List of recipient email(s)
subject: Email subject
body: Email body
cc: List of CC recipients (optional)
bcc: List of BCC recipients (optional)
attachment: Path to file to attach (optional)

`async_send_email(config, recipient, subject, body, cc=None, bcc=None, attachment=None)`

Sends an email asynchronously (non-blocking, returns an awaitable).

config: EmailConfig instance
recipient: List of recipient email(s)
subject: Email subject
body: Email body
cc: List of CC recipients (optional)
bcc: List of BCC recipients (optional)
attachment: Path to file to attach (optional)

Development

Rust dependencies are managed in Cargo.toml.
Python build configuration is in pyproject.toml.
Main Rust logic in src/.

License

MIT

simple_smtp_sender 0.2.5