open-messaging

Provider-agnostic transactional messaging port (email-first).

There is no useful open standard for SaaS transactional send across ESPs. This package owns a small hexagonal MessagingProvider port and ships adapters.

Install

npm install open-messaging

Quick start

import { getMessagingProvider } from 'open-messaging';

const messaging = getMessagingProvider(); // EMAIL_PROVIDER / MESSAGING_PROVIDER, default resend

await messaging.send({
  to: '[email protected]',
  subject: 'Welcome',
  html: '<p>Hello</p>',
  tags: { category: 'welcome' },
});

Env

MESSAGING_PROVIDER=resend   # alias: EMAIL_PROVIDER
EMAIL_FROM=App <[email protected]>
RESEND_API_KEY=

When RESEND_API_KEY is unset, sends are mocked ({ mocked: true, ok: true }).

Supported providers (v0.1)

| Id | Adapter | |---|---| | resend | adapters/resend |

Additional ESPs (Postmark, SES, SendGrid, …) can register on the same port later.

License

MIT

Testing / mocks

import { createMockMessagingProvider, fixtureSendInput } from 'open-messaging/testing';
import { setMessagingProviderOverride, getMessagingProvider } from 'open-messaging';

const mock = createMockMessagingProvider({ id: 'resend' });
setMessagingProviderOverride(mock);
await getMessagingProvider().send(fixtureSendInput);
expect(mock.calls.send).toHaveLength(1);

With RESEND_API_KEY unset, the Resend adapter mock-sends. With the key set, unit tests can stub fetch.