MailerSend

The @effect-kit/emails/mailersend subpath sends messages through MailerSend and provides the Email service.

InstallationCopy Anchor Link

npm install @effect-kit/emails effect mailersend@3.6.0

The SDK is a pinned optional peer. It is needed only when you import this subpath.

SetupCopy Anchor Link

MailerSend.layerConfig() reads these variables:

Example (Sending a Message With MailerSend)

import { ConfigProvider, Effect, Layer } from "effect";
import { Email } from "@effect-kit/emails";
import * as MailerSend from "@effect-kit/emails/mailersend";

const EmailLive = MailerSend.layerConfig().pipe(
  Layer.provide(ConfigProvider.layer(ConfigProvider.fromEnv())),
);

const program = Effect.gen(function* () {
  const email = yield* Email;
  return yield* email.send({
    from: "hello@example.com",
    to: "ada@example.com",
    subject: "Welcome",
    text: "Your account is ready.",
  });
});

Effect.runPromise(program.pipe(Effect.provide(EmailLive)));

Use a from address your MailerSend account is allowed to send from.

OptionsCopy Anchor Link

MailerSend.layer takes these options. layerConfig builds the same object from a Config.

CapabilitiesCopy Anchor Link

MailerSend reports this in email.capabilities:

These fail with UnsupportedFeatureError and acceptance: "notSubmitted" before any request:

• More than one replyTo address (feature multipleReplyTo).
• Any attachment (feature attachments).
• An idempotencyKey (feature idempotency).

IdempotencyCopy Anchor Link

Not supported. A key fails with UnsupportedFeatureError before sending.

Provider notesCopy Anchor Link

• MailerSend takes one reply-to address and no attachments through this package. Both fail before sending.
• Header names may contain only letters, digits and hyphens. Any other name fails with InvalidMessageError (path headers) and acceptance: "notSubmitted".
• A send is accepted only on an HTTP 202 response. If MailerSend reports suppressed recipients, the receipt is partiallyAccepted with one outcome per recipient. When every recipient is suppressed the send fails with MessageRejectedError.

Using your own clientCopy Anchor Link

layerClient takes any object with email.send(message), which a MailerSend client has. options is optional. The client must return the response object with statusCode, headers and body, which is what the SDK does.

Example (Borrowing a MailerSend Client)

import { MailerSend } from "mailersend";
import * as MailerSendEmail from "@effect-kit/emails/mailersend";

const client = new MailerSend({ apiKey: "fake-key" });

const EmailLive = MailerSendEmail.layerClient(client);

You own a borrowed client. The Layer never closes it, and the client keeps its own retry, timeout and logging policy.

ErrorsCopy Anchor Link

ProviderConfigurationError carries provider: "mailersend" and a field naming the bad option. Layer construction fails with it, and layerClient fails with it for the client options.

Any other HTTP status uses the shared mapping: 401 is AuthenticationError, 403 PermissionDeniedError, 429 RateLimitedError, 400 and 422 InvalidMessageError, 5xx ProviderUnavailableError, and anything else ProviderError. acceptance is rejected for a 4xx status other than 409 and unknown otherwise. See Errors. A network failure with no status is TransportError, and ETIMEDOUT or ECONNABORTED is TimeoutError, both with acceptance: "unknown".