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Quick setup examples

Axum

Send your first email from an Axum handler using reqwest against the MailBlastr API.

Rust has an official SDK — the `mailblastr` crate on crates.io — and an Axum handler can call it directly on the Tokio runtime. The example below instead takes the raw-HTTP route, POSTing JSON to https://www.mailblastr.com/api/emails with the async `reqwest` client, so you can see exactly what goes over the wire.

Prerequisites

1. Install dependencies

Add Axum, an async HTTP client, a runtime, and JSON support to your Cargo project.

cargo add axum
cargo add reqwest -F json
cargo add tokio -F macros,rt-multi-thread
cargo add serde_json

2. Set your API key

.env
MAILBLASTR_API_KEY=mb_xxxxxxxxx

3. Send an email

Build an Axum router with a single route whose handler POSTs the email and returns the created id.

src/main.rs
use axum::{http::StatusCode, routing::get, Router};
use serde_json::json;

#[tokio::main]
async fn main() {
    let app = Router::new().route("/", get(endpoint));

    let listener = tokio::net::TcpListener::bind("0.0.0.0:3000")
        .await
        .unwrap();
    axum::serve(listener, app).await.unwrap();
}

async fn endpoint() -> Result<String, StatusCode> {
    let api_key = std::env::var("MAILBLASTR_API_KEY")
        .map_err(|_| StatusCode::INTERNAL_SERVER_ERROR)?;

    let res = reqwest::Client::new()
        .post("https://www.mailblastr.com/api/emails")
        .bearer_auth(api_key)
        // reqwest sends no User-Agent of its own and the API rejects a request
        // without one with 403 validation_error, so set it explicitly.
        .header("User-Agent", "my-app/1.0")
        .json(&json!({
            "from": "Acme <onboarding@yourdomain.com>",
            "to": ["delivered@mailblastr.dev"],
            "subject": "Hello World",
            "html": "<strong>It works!</strong>",
        }))
        .send()
        .await
        .map_err(|_| StatusCode::INTERNAL_SERVER_ERROR)?;

    let body: serde_json::Value = res
        .json()
        .await
        .map_err(|_| StatusCode::INTERNAL_SERVER_ERROR)?;

    Ok(body["id"].to_string())
}

Opening your browser at http://localhost:3000 (or running curl localhost:3000) sends an email and returns its id.

The explicit User-Agent header is required: reqwest does not set one by default and every MailBlastr API request without a User-Agent is rejected with 403 validation_error. The official crate sets it for you.
See Send an email for the full body schema — cc, bcc, reply_to, attachments, and more.