BirrJS

The @birrjs/email-resend plugin sends email notifications to customers when subscription events occur — payment received, payment failed, subscription expired, or expiring soon.

Installation

pnpm add @birrjs/email-resend

Configuration

import { resend } from "@birrjs/email-resend";
import { createBirr } from "@birrjs/core";

createBirr({
  // ... other options
  plugins: [
    resend({
      apiKey: process.env.RESEND_API_KEY!,
      from: "Acme <notifications@acme.com>",
    }),
  ],
});

Environment variables

Variable	Required	Description
`RESEND_API_KEY`	Yes	API key from resend.com

Options

Option	Type	Default	Description
`apiKey`	`string`	—	Resend API key
`from`	`string`	—	Sender address, e.g. `"Acme <noreply@acme.com>"`
`subject`	`object`	(defaults below)	Override email subjects per event
`messages`	`object`	(defaults below)	Override HTML templates per event

How it works

The plugin listens to subscription lifecycle events via the onEvent hook system and sends an HTML email to the customer's email address.

Event	Default subject	Default body
`subscription.activated`	Payment received	`<h1>Payment received</h1><p>Thank you, {name}. You are now subscribed to {planName}.</p>`
`subscription.cancelled`	Payment failed	`<h1>Payment failed</h1><p>{name}, your payment for {planName} could not be processed. Please update your payment method.</p>`
`subscription.expired`	Subscription expired	`<h1>Subscription expired</h1><p>{name}, your {planName} subscription has expired. Renew now to continue access.</p>`
`subscription.reminder`	Reminder: subscription expires soon	`<h1>Renewal reminder</h1><p>{name}, your {planName} subscription expires in {daysUntil} days. Renew now to avoid interruption.</p>`

Customer email

The email address is read from the birrjs_customer.email column. Set it on your customer record — typically by returning email from your identify function:

identify: async (request) => {
  const session = await auth.api.getSession({ headers: request.headers });
  return {
    customerId: session.user.id,
    email: session.user.email, 
  };
},

If the customer has no email when an event fires, the email is silently skipped. For subscription.reminder events, the email comes directly from the event payload.

Custom messages

Override default subjects and HTML templates:

resend({
  subject: {
    paymentReceived: "You're subscribed!",
    paymentFailed: "Action needed: payment failed",
  },
  messages: {
    paymentReceived: "<h1>Welcome!</h1><p>Thanks {name}.</p>",
    paymentFailed: "<h1>Payment issue</h1><p>Please update your payment method.</p>",
  },
})

Template variables are enclosed in {curly braces}:

Variable	Available in
`{name}`	All events
`{planName}`	All events
`{daysUntil}`	`subscription.reminder` only

Resend Email