eusend

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

InstallationCopy Anchor Link

npm install @effect-kit/emails effect @eusend_dev/sdk@0.19.0

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

SetupCopy Anchor Link

Eusend.layerConfig() reads these variables:

Example (Sending a Message With eusend)

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

const EmailLive = Eusend.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 eusend account is allowed to send from.

OptionsCopy Anchor Link

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

CapabilitiesCopy Anchor Link

eusend reports this in email.capabilities:

Every message feature is supported, so no message fails the capability check.

IdempotencyCopy Anchor Link

Mode replay, with no retention declared. The package passes the key to eusend as the SDK's idempotencyKey option.

The key must be 1 to 255 printable ASCII characters and not blank, otherwise the send fails with InvalidMessageError (path idempotencyKey) and acceptance: "notSubmitted". A CONFLICT error from eusend fails with IdempotencyConflictError.

Example (Sending With an Idempotency Key)

import { Effect } from "effect";
import { Email } from "@effect-kit/emails";

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.",
    },
    { idempotencyKey: "welcome-ada-2026-10-29" },
  );
});

Provider notesCopy Anchor Link

The receipt's requestId comes from the x-request-id response header when eusend returns one.

Using your own clientCopy Anchor Link

layerClient takes any object with emails.send(message, { idempotencyKey }), which an Eusend client has. options is optional.

Example (Borrowing a eusend Client)

import { Eusend as EusendSdk } from "@eusend_dev/sdk";
import * as Eusend from "@effect-kit/emails/eusend";

const client = new EusendSdk("fake-key");

const EmailLive = Eusend.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: "eusend" and a field naming the bad option. Layer construction fails with it, and layerClient fails with it for the client options.

The error name is kept as providerCode and its status as statusCode. Names not listed use the status with the shared mapping.