MkSaaS DocsNewsletter
Learn how to set up and use Resend or Beehiiv for newsletter management
MkSaaS supports Resend and Beehiiv for managing newsletter subscriptions.
Setup
Create Resend Account
Create a Resend account at resend.com.
Get API Key
Click API Keys > Create API Key in the dashboard, set the permissions to Send emails or Full access. Get the API key from the dashboard, and add it to the environment variables file:
RESEND_API_KEY=YOUR-RESEND-API-KEYUpdate Website Configuration
export const websiteConfig = {
// ...other config
newsletter: {
enable: true,
provider: 'resend',
autoSubscribeAfterSignUp: false,
},
// ...other config
}If you are setting up the environment, now you can go back to the Environment Setup guide and continue. The rest of this guide can be read later.
Environment Setup
Set up environment variables
Usage
import { subscribe, unsubscribe, isSubscribed } from '@/newsletter';
// Subscribe a user to the newsletter
const success = await subscribe('user@example.com');
// Unsubscribe a user from the newsletter
const success = await unsubscribe('user@example.com');
// Check if a user is subscribed
const subscribed = await isSubscribed('user@example.com');Email addresses are trimmed and converted to lowercase before they are sent to
the provider. When autoSubscribeAfterSignUp is enabled, signup schedules the
subscription asynchronously after a short delay so newsletter failures do not
block account creation. The welcome email is scheduled separately.
The Resend provider uses the Contacts API without an audience ID. It first tries to create the contact and falls back to updating an existing contact, making repeat subscriptions safe.
Extending New Newsletter Providers
MkSaaS supports extending with new newsletter providers:
- Create a new file in the
src/newsletter/providerdirectory (e.g.,custom-provider.ts). - Implement the
NewsletterProviderinterface:
import type {
CheckSubscribeStatusParams,
NewsletterProvider,
SubscribeNewsletterParams,
UnsubscribeNewsletterParams,
} from '@/newsletter/types';
export class CustomNewsletterProvider implements NewsletterProvider {
constructor() {
// Initialize your provider
}
public getProviderName(): string {
return 'CustomProvider';
}
async subscribe({ email }: SubscribeNewsletterParams): Promise<boolean> {
// Implementation for subscribing a user
return true;
}
async unsubscribe({ email }: UnsubscribeNewsletterParams): Promise<boolean> {
// Implementation for unsubscribing a user
return true;
}
async checkSubscribeStatus({ email }: CheckSubscribeStatusParams): Promise<boolean> {
// Implementation for checking subscription status
return true;
}
}- Add the provider name to
NewsletterConfig['provider']insrc/types/index.d.ts, then register its lazy factory inindex.ts:
import { CustomNewsletterProvider } from './provider/custom-provider';
const providerRegistry: Partial<
Record<NewsletterProviderName, NewsletterProviderFactory>
> = {
resend: () => new ResendNewsletterProvider(),
beehiiv: () => new BeehiivNewsletterProvider(),
custom: () => new CustomNewsletterProvider(),
};FAQ
Which provider should I choose?
- Choose Resend if you already use Resend for transactional emails and want a simple, unified solution for both email sending and newsletter management.
- Choose Beehiiv if you need advanced newsletter features like analytics, monetization, referral programs, and growth tools for professional content creators.
RESEND_AUDIENCE_ID Environment Variable
As of November 15, 2025, the RESEND_AUDIENCE_ID environment variable has been removed from the template, and the newsletter module no longer needs this environment variable.
Please refer to the documentation for more details: Migrating from Audiences to Segments