Send email from Cloudflare Workers via MailChannels

Cloudflare announced a partnership with MailChannels that allows you to send free email via workers.

The example code that MailChannels supplied wasn't working so I fixed it here to make testing easy.

Add include:relay.mailchannels.net to your domain's SPF record.
Update the code below with your email addresses
Create worker, paste code, save and deploy and test

Follow Adam Sculthorpe on Twitter if you have questions or found this useful.

addEventListener("fetch", event => {
    event.respondWith(handleRequest(event.request))
})

async function handleRequest(request) {
    let content = "";
    for( var i of request.headers.entries() ) {
        content += i[0] + ": " + i[1] + "\n";
    }
    let send_request = new Request("https://api.mailchannels.net/tx/v1/send", {
        "method": "POST",
        "headers": {
            "content-type": "application/json",
        },
        "body": JSON.stringify({
            "personalizations": [
                { "to": [ {"email": "receive@yourdomain.com",
                        "name": "Test Recipient"}]}
            ],
            "from": {
                "email": "send@yourdomain.com",
                "name": "Test Sender",
            },
            "subject": "Test Subject",
            "content": [{
                "type": "text/plain",
                "value": "Test message content\n\n" + content,
            }],
        }),
    });

    let respContent = "";
    // only send the mail on "POST", to avoid spiders, etc.
    if( request.method == "POST" ) {
        const resp = await fetch(send_request);
        const respText = await resp.text();
        respContent = resp.status + " " + resp.statusText + "\n\n" + respText;
    }

    let htmlContent = "<html><head></head><body><pre>" + "</pre><p>Click to send message: <form method='post'><input type='submit' value='Send'/></form></p>" + "<pre>" + respContent + "</pre>" + "</body></html>";
    return new Response(htmlContent, {
        headers: { "content-type": "text/html" },
    })
}

stonking/cf-worker-email.md

Send email from Cloudflare Workers via MailChannels