ZeptoMail transport

The ZeptoMail transport sends through the email API of ZeptoMail, the transactional service of Zoho, from the ZeptoMail driver of unemail.

Installation

pnpm add @alexify/mailer
# or
npm install @alexify/mailer

Basic usage

const { createMessage } = require('@alexify/mailer');
const { ZeptoMailTransport } = require('@alexify/mailer/zeptomail');

const transport = new ZeptoMailTransport({
  token: process.env.ZEPTOMAIL_TOKEN,
  bounceAddress: 'bounce@bounces.example.com',
});

const receipt = await transport.send(
  createMessage({
    from: 'Shop <shop@example.com>',
    to: 'user@example.com',
    subject: 'Your order has shipped',
    content: { html: '<p>On its way.</p>' },
    tags: ['order-42'],
  }),
);
if (receipt.successful) console.log(receipt.messageId); // the request_id

Options

Option	Default	Description
token	(required)	The Send Mail token of a Mail Agent; Zoho-enczapikey is added unless it is there.
baseUrl	https://api.zeptomail.com	HTTPS, or HTTP to this machine; the host of the account's data center, such as https://api.zeptomail.eu.
bounceAddress		The bounce address, on a bounce domain verified with ZeptoMail.
clientReference		The client_reference of a message without a tag.
openTracking, clickTracking	the agent's	Tracking, unless a message sets its own tracking.
concurrency	5	The most requests of sendMany() at once.
timeout	30000	Milliseconds a request may take; 0 or Infinity for none.
retries	3	Retries of a request that failed before ZeptoMail took it.
headers		Header fields added to every request.
fetch, logger, generateId		As for every transport.

What a message becomes

• ZeptoMail has no tags: a message's one tag is its client_reference, which its reports and events show; a second tag is refused.
• metadata goes in X-Metadata-<key> headers (mime_headers), with custom header fields, List-* and the threading fields; tracking is track_opens and track_clicks.
• An inline attachment goes in inline_images with its Content-ID as cid.
• ZeptoMail takes 500 addresses in each of to, cc and bcc, 60 attachments and a subject of 500 characters; more are refused before the request. It cannot schedule a message, so scheduledAt is refused as unsupported.

ZeptoMail answers 201 with a request_id, the receipt's id; an answer without one is reported as deliveryUnknown. The code in the details of an error says more than its status: an invalid token (SERR_157) is auth, a rate limit (SM_133) rate-limit, spent credits (LE_101, LE_102) configuration, and a malformed request (TM_3201, TM_3301, TM_8001) validation.

Batches

sendMany() sends concurrency single requests at a time, each with its own receipt. The batch endpoint is not used: it sends one message to many recipients, with one answer for all of them.

Verifying the configuration

This transport has no verify(): a Send Mail token can only send, and ZeptoMail offers no request that checks it.