Mailgun Scheduler

A Node.js library for scheduling sequential emails.
Use this library in combination with Mailgun webhooks. Webhook handler will send as many emails as are provided in templates argument, and tracks the current status using an inbuilt custom variable.

Mailgun only allows delayed sending of up to three days. This library allows you to schedule followup emails on delivery of previous email, allowing scheduled emails to exceed this time limit past the first email delivery date.

Installation

npm install mailgun-scheduler

Options

Mailgun Scheduler is based on mailgun-js and accepts the same options for the initialising call. Required arguments are apiKey and domain.

Example usage

const mgScheduler = require("mailgun-scheduler");

const scheduler = mgScheduler({
  apiKey: process.env.MAILGUN_API_KEY,
  domain: process.env.MAILGUN_DOMAIN,
});

const delay = 60 x 60 x 48; // Two days as seconds

const templates: [
  {
    subject: "Greetings",
    text: "My first email."
  },
  {
    subject: "Hello again",
    text: "A follow up email"
  },
  {
    subject: "That's all for now",
    text: "Another follow up email"
  }
]

// Sends first email immediately (unless delay property added)
scheduler.start({
  to: "[email protected]",
  from: "[email protected]",
  templates,
  customVars: {
    clientId: "44845kjrngu8"
  }
});

// Handles mailgun events - schedules followup emails
const processMailgunEvent = async (payload) => {
  try {
    const customVars = eventData["user-variables"];
    await validateId(customVars.clientId);

    const eventData = payload["event-data"];
    if (eventData.event === "delivered") {
      // Schedule next email once current email has been delivered
      return await emailService.handleWebhook({
        delay,
        payload,
        templates,
      });
    }
  } catch (err) {
    console.log(err)
  }
}

// Mailgun allows unsubscribe links in emails which is handled automatically,
// however if you want to unsubscribe an address via the API:
const manualUnsubscribe = async (email) => {
  try {
    return await scheduler.handleUnsubscribe(email);
  } catch (err) {
    console.log(err)
  }
}