Node.js SDK

Send email with Fastify

Use Parcel Wing from Fastify routes, plugins, and typed handlers while keeping API keys server-side.

Install the SDK

The official SDK is published as @parcelwing/node.

Terminal

npm install @parcelwing/node

Plugin

src/plugins/parcelwing.ts

import fp from "fastify-plugin";
import { ParcelWing } from "@parcelwing/node";
 
export default fp(async (fastify) => {
  const parcelWing = new ParcelWing({
    apiKey: process.env.PARCEL_WING_API_KEY!,
  });
 
  fastify.decorate("parcelWing", parcelWing);
});
 
declare module "fastify" {
  interface FastifyInstance {
    parcelWing: ParcelWing;
  }
}

Route

Use the decorated SDK client inside a typed route handler and return structured errors when Parcel Wing rejects the request.

src/server.ts

import Fastify from "fastify";
import { ParcelWingError } from "@parcelwing/node";
import parcelWingPlugin from "./plugins/parcelwing";
 
const fastify = Fastify({ logger: true });
await fastify.register(parcelWingPlugin);
 
fastify.post<{ Body: { email: string; firstName?: string } }>(
  "/send-welcome",
  async (request, reply) => {
    try {
      const [message] = await fastify.parcelWing.emails.send({
        from: "Acme <[email protected]>",
        to: request.body.email,
        template_alias: "welcome_email",
        template_params: {
          first_name: request.body.firstName ?? "friend",
        },
      });
 
      return { id: message?.id };
    } catch (error) {
      if (error instanceof ParcelWingError) {
        return reply.status(error.status).send({
          code: error.code,
          requestId: error.requestId,
        });
      }
 
      request.log.error(error);
      return reply.status(500).send({ error: "Unexpected error" });
    }
  },
);
 
await fastify.listen({ port: Number(process.env.PORT ?? 3000), host: "0.0.0.0" });

Production notes

Keep PARCEL_WING_API_KEY in server-only environment variables.
Validate public request bodies with your preferred Fastify schema before sending.
Log requestId from ParcelWingError for easier support and debugging.