Resend Convex Component

This component is the official way to integrate the Resend email service with your Convex project.

Features:

• Queueing: Send as many emails as you want, as fast as you want—they'll all be delivered (eventually).
• Batching: Automatically batches large groups of emails and sends them to Resend's /emails/batch endpoint efficiently.
• Durable execution: Uses Convex workpools to ensure emails are eventually delivered, even in the face of temporary failures or network outages.
• Idempotency: Manages Resend idempotency keys to guarantee emails are delivered exactly once, preventing accidental spamming from retries.
• Rate limiting: Honors API rate limits established by Resend.

See example for a demo of how to incorporate this hook into your application.

Installation

npm install @convex-dev/resend

Get Started

Create a Resend account and grab an API key. Set it to RESEND_API_KEY in your deployment environment.

Next, add the component to your Convex app via convex/convex.config.ts:

import { defineApp } from "convex/server";
import resend from "@convex-dev/resend/convex.config.js";

const app = defineApp();
app.use(resend);

export default app;

Then you can use it, as we see in convex/sendEmails.ts:

import { components } from "./_generated/api";
import { Resend } from "@convex-dev/resend";
import { internalMutation } from "./_generated/server";

export const resend: Resend = new Resend(components.resend, {});

export const sendTestEmail = internalMutation({
  handler: async (ctx) => {
    await resend.sendEmail(ctx, {
      from: "Me <[email protected]>",
      to: "[email protected]",
      subject: "Hi there",
      html: "This is a test email",
    });
  },
});

Then, calling sendTestEmail from anywhere in your app will send this test email.

If you want to send emails to real addresses, you need to disable testMode. You can do this in ResendOptions, as detailed below.

A note on test email addresses: Resend allows the use of labels for test emails. For simplicity, this component only allows labels matching [a-zA-Z0-9_-]*, e.g. [email protected].

Advanced Usage

Setting up a Resend webhook

While the setup we have so far will reliably send emails, you don't have any feedback on anything delivering, bouncing, or triggering spam complaints. For that, we need to set up a webhook!

On the Convex side, we need to mount an http endpoint to our project to route it to the Resend component in convex/http.ts:

import { httpRouter } from "convex/server";
import { httpAction } from "./_generated/server";
import { resend } from "./sendEmails";

const http = httpRouter();

http.route({
  path: "/resend-webhook",
  method: "POST",
  handler: httpAction(async (ctx, req) => {
    return await resend.handleResendEventWebhook(ctx, req);
  }),
});

export default http;

If our Convex project is happy-leopard-123, we now have a Resend webhook for our project running at https://happy-leopard-123.convex.site/resend-webhook.

So navigate to the Resend dashboard and create a new webhook at that URL. Make sure to enable all the email.* events; the other event types will be ignored.

Finally, copy the webhook secret out of the Resend dashboard and set it to the RESEND_WEBHOOK_SECRET environment variable in your Convex deployment.

You should now be seeing email status updates as Resend makes progress on your batches!

Speaking of...

Registering an email status event handler.

If you have your webhook established, you can also register an event handler in your apps you get notifications when email statuses change.

Update your sendEmails.ts to look something like this:

import { components, internal } from "./_generated/api";
import { internalMutation } from "./_generated/server";
import { vEmailId, vEmailEvent, Resend } from "@convex-dev/resend";

export const resend: Resend = new Resend(components.resend, {
  onEmailEvent: internal.example.handleEmailEvent,
});

export const handleEmailEvent = internalMutation({
  args: vOnEmailEventArgs,
  handler: async (ctx, args) => {
    // Handle however you want
    // args provides { id: EmailId; event: EmailEvent; }
    // see /example/example.ts
  },
});

Check out the example/ project in this repo for a full demo.

Resend component options, and going into production

There is a ResendOptions argument to the component constructor to help customize it's behavior.

Check out the docstrings, but notable options include:

• apiKey: Provide the Resend API key instead of having it read from the environment variable.
• webhookSecret: Same thing, but for the webhook secret.
• testMode: Only allow delivery to test addresses. To keep you safe as you develop your project, testMode is default true. You need to explicitly set this to false for the component to allow you to enqueue emails to artibrary addresses.
• onEmailEvent: Your email event callback, as outlined above! Check out the docstrings for details on the events that are emitted.

Optional email sending parameters

In addition to basic from/to/subject and html/plain text bodies, the sendEmail method allows you to provide a list of replyTo addresses, and other email headers.

Enqueue-time idempotency

The component already sends idempotency keys to Resend so a given batch is delivered at most once. That protects against the component retrying an API call, but it doesn't stop your application from enqueuing the same logical email twice (for example, when a business flow re-fires or an action is retried).

To dedupe at enqueue time, pass an idempotencyKey. If an email with the same key has already been enqueued, sendEmail returns the existing EmailId instead of enqueuing (and delivering) a duplicate:

const emailId = await resend.sendEmail(ctx, {
  from: "Me <[email protected]>",
  to: "[email protected]",
  subject: "Order confirmation",
  html: "...",
  // Derive this from the triggering event so retries collapse to one send.
  idempotencyKey: `order-confirmation:${orderId}`,
});

Because sendEmail runs in a transactional mutation, concurrent enqueues with the same key are safe: one wins and the others receive its EmailId.

Using Resend Templates

You can use Resend templates to send emails with pre-designed templates from your Resend dashboard. To use a template, provide the template ID and any required template variables:

await resend.sendEmail(ctx, {
  from: "Me <[email protected]>",
  to: "[email protected]",
  subject: "Welcome to our app",
  template: {
    id: "my-template-id",
    variables: {
      name: "John Doe",
      verificationLink: "https://example.com/verify?token=abc123",
    },
  },
});

[!IMPORTANT] You cannot use both template and html/text in the same email. If you need to send dynamic HTML content, either use templates with template variables, or use the html/text fields directly (optionally with React Email).

Tracking, getting status, and cancelling emails

The sendEmail method returns a branded type, EmailId. You can use this for a few things:

• To reassociate the original email during status changes in your email event handler.
• To check on the status any time using resend.status(ctx, emailId).
• To cancel the email using resend.cancelEmail(ctx, emailId).

If the email has already been sent to the Resend API, it cannot be cancelled. Cancellations do not trigger an email event.

Checking email status programmatically

Use the status method to check an email's current state:

const emailStatus = await resend.status(ctx, emailId);
if (emailStatus) {
  console.log(emailStatus.status); // e.g., "delivered", "bounced", "sent"
  console.log(emailStatus.bounced); // boolean
  console.log(emailStatus.failed); // boolean
  console.log(emailStatus.complained); // spam complaint (boolean)
  console.log(emailStatus.deliveryDelayed); // boolean
  console.log(emailStatus.opened); // if open tracking enabled (boolean)
  console.log(emailStatus.clicked); // if click tracking enabled (boolean)
  console.log(emailStatus.errorMessage); // error details (string | null)
}

Viewing emails and webhook events in the dashboard

You can view all email data directly in your Convex dashboard in the component's data view. Click the drop down with a puzzle piece that says app:

1. Emails table: Navigate to your Convex dashboard → Data. Choose resend from the component drop down then choose the emails table. This shows all emails with their current status, recipients, subjects, and tracking information.

2. Delivery Events table: Navigate to Components → resend → deliveryEvents table. This table stores all webhook events received from Resend, including:

   • emailId: Links back to the email in the emails table
   • resendId: Resend's ID for the email
   • eventType: The type of event (e.g., email.delivered, email.bounced, email.opened, email.clicked, email.complained)
   • createdAt: When the event occurred
   • message: Additional details (e.g., bounce reasons)

This is useful for debugging delivery issues, viewing email history, and understanding what happened with each email you sent.

Data retention

This component retains "finalized" (delivered, cancelled, bounced) emails. It's your responsibility to clear out those emails on your own schedule. You can run cleanupOldEmails and cleanupAbandonedEmails from the dashboard, under the "resend" component tab in the function runner, or set up a cron job.

If you pass no argument, it defaults to deleting emails older than 7 days.

If you don't care about historical email status, the recommended approach is to use a cron job, as shown below:

// in convex/crons.ts
import { cronJobs } from "convex/server";
import { components, internal } from "./_generated/api.js";
import { internalMutation } from "./_generated/server.js";

const crons = cronJobs();
crons.interval(
  "Remove old emails from the resend component",
  { hours: 1 },
  internal.crons.cleanupResend,
);

const ONE_WEEK_MS = 7 * 24 * 60 * 60 * 1000;
export const cleanupResend = internalMutation({
  args: {},
  handler: async (ctx) => {
    await ctx.scheduler.runAfter(0, components.resend.lib.cleanupOldEmails, {
      olderThan: ONE_WEEK_MS,
    });
    await ctx.scheduler.runAfter(
      0,
      components.resend.lib.cleanupAbandonedEmails,
      // These generally indicate a bug, so keep them around for longer.
      { olderThan: 4 * ONE_WEEK_MS },
    );
  },
});

export default crons;

Using React Email

You can use React Email to generate your HTML for you from JSX.

First install the dependencies:

npm install @react-email/components react react-dom react-email @react-email/render

Then create a new .tsx file in your Convex directory e.g. /convex/emails.tsx:

// IMPORTANT: this is a Convex Node Action
"use node";
import { action } from "./_generated/server";
import { render, pretty } from "@react-email/render";
import { Button, Html } from "@react-email/components";
import { components } from "./_generated/api";
import { Resend } from "@convex-dev/resend";

export const resend: Resend = new Resend(components.resend, {
  testMode: false,
});

export const sendEmail = action({
  args: {},
  handler: async (ctx, args) => {
    // 1. Generate the HTML from your JSX
    // This can come from a custom component in your /emails/ directory
    // if you would like to view your templates locally. For more info see:
    // https://react.email/docs/getting-started/manual-setup#5-run-locally
    const html = await pretty(
      await render(
        <Html>
          <Button
            href="https://example.com"
            style={{ background: "#000", color: "#fff", padding: "12px 20px" }}
          >
            Click me
          </Button>
        </Html>,
      ),
    );

    // 2. Send your email as usual using the component
    await resend.sendEmail(ctx, {
      from: "Me <[email protected]>",
      to: "[email protected]",
      subject: "Hi there",
      html,
    });
  },
});

[!WARNING] React Email requires some Node dependencies thus it must run in a Convex Node action and not a regular Action.

Sending emails manually, e.g. for attachments

If you need something that the component doesn't provide (it is currently limited by what is supported by the batch API in Resend), you can send emails manually using sendEmailManually. Unlike sendEmail which enqueues emails and sends them in batches via the /emails/batch endpoint, sendEmailManually calls Resend's /emails endpoint directly without enqueueing. This gives you fine-grained control over the email sending process while still tracking its progress using the component's status and webhook APIs.

import { components, internal } from "./_generated/api";
import { internalAction } from "./_generated/server";
import { Resend as ResendComponent } from "@convex-dev/resend";
import { Resend } from "resend";

const resendSdk = new Resend("re_xxxxxxxxx");

export const resend = new ResendComponent(components.resend, {});

export const sendManualEmail = internalAction({
  args: {},
  handler: async (ctx, args) => {
    const from = "Acme <[email protected]>";
    const to = ["[email protected]"];
    const subject = "hello world";
    const html = "<p>it works!</p>";

    const emailId = await resend.sendEmailManually(
      ctx,
      { from, to, subject },
      async (emailId) => {
        const {data, error} = await resendSdk.emails.send({
          from,
          to,
          subject,
          html,
          headers: {
            "Idempotency-Key": emailId,
          },
        });
        if (error) {
          throw new Error(`[Email] Failed to send: ${error.message}`);
        }
        return data.id!;
      },
    );
  },
});

Use sendEmailManually when you need features not supported by the batch API, such as attachments, or when you want to send an email immediately without waiting for the batching system.