mail

Sending mail from a Lumen program. One Mailer interface, one module per service, one HTML shell.

export type Mailer = {
  name: string,
  credential: string,
  deliver: (key: string, message: MailMessage) => MailReply,
};

Ships with resend.ts and sendgrid.ts.

Use

import { MailAsk, MailPost, mailWith } from "./mail.ts";
import { resendMailer } from "./resend.ts";

let post: MailPost = {
  from: "Joule <hello@joule.sh>",
  replyTo: "",
  key: apiKey,                       // already decrypted; this package reads no key store
  brand: "Joule",
  footer: "Sent by an agent on Joule.",
};
let ask: MailAsk = {
  to: "someone@example.com, another@example.com",
  subject: "Weekly report",
  body: "All quiet.\n\nNothing needed your attention this week.",
};

let sent = mailWith(resendMailer(), post, ask);
if (!sent.ok) {
  print(sent.fault);
}

The body is prose. Blank lines become paragraphs, single newlines become breaks, and the plain-text part is what you wrote, unchanged.

from comes from the caller, never from the message.

Refused before a request

an address that is not one — and the whole list, not the addresses either side of the typo
more than ten recipients
a newline in the subject
an empty subject or body
a body over 100,000 characters

Answers

mailWith says whether the service accepted the message. Whether it arrived is the service's own webhooks; MailReply.id is kept so a program can ask later. SendGrid returns 202 with no body, so id is empty there.

Adding a service

A module with a deliver and a constructor, and a line wherever your program picks one. mail.ts does not change.