Crate direct_to_mx 

direct_to_mx

Direct-to-MX email delivery with DKIM signing, IPv4 forcing, MX fallback, DKIM key generation, and DNS verification.

This crate provides a builder-based API for sending emails directly to recipient MX servers without relying on an intermediate relay or third-party API. It handles MX resolution, IPv4-only connections (to avoid IPv6 PTR rejections), opportunistic TLS, DKIM signing with relaxed/relaxed canonicalization, and automatic fallback across multiple MX hosts.

Example

use direct_to_mx::{DirectToMx, Body, DkimOptions};

let mailer = DirectToMx::builder()
    .from("no-reply@mail.example.com")
    .ehlo_hostname("mail.example.com")
    .dkim(DkimOptions {
        selector: "sel1".into(),
        domain: "mail.example.com".into(),
        private_key_pem: std::fs::read_to_string("/path/to/dkim.pem").unwrap(),
    })
    .build()?;

mailer.send("user@gmail.com", "Hello", Body::text("Hi there")).await?;

Re-exports

pub use dkim::DkimKeyPair;

pub use dkim::generate_dkim_keypair;

pub use dns::DnsCheck;

pub use dns::DnsCheckResult;

pub use dns::DnsCheckStatus;

pub use dns::DnsVerifyOptions;

pub use dns::DnsVerifyReport;

pub use dns::verify_dns;

pub use error::DirectToMxError;

Modules

dkim

dns

error

Structs

Attachment

A file attachment.

BulkResult

Result of a single delivery within a bulk send.

DirectToMx

The configured mailer. Obtain one via DirectToMx::builder().

DirectToMxBuilder

Builder for DirectToMx.

DkimOptions

DKIM signing configuration.

OutboundMessage

A single outbound message for DirectToMx::send_bulk.

Enums

Body

Email body — HTML, plain text, or both (multipart/alternative).

Constants

DEFAULT_CONCURRENCY

Default number of concurrent SMTP deliveries for DirectToMx::send_bulk.