Batch Sending

Batch sending allows you to send multiple emails at once (up to 100) instead of making individual API requests for each email.

When to use batch sending

Use batch sending when you need to:

Send multiple transactional emails (e.g., order confirmations and notifications)
Trigger emails to different recipients with unique content
Reduce the number of API calls to improve performance

Send batch emails

You can send up to 100 emails in a single API call using the batch endpoint. Each email in the batch can have different recipients, subjects, and content.

Node.js

import { Resend } from 'resend';

const resend = new Resend('re_xxxxxxxxx');

const { data, error } = await resend.batch.send([
  {
    from: 'Acme <onboarding@resend.dev>',
    to: ['delivered@resend.dev'],
    subject: 'Welcome to Acme',
    html: '<p>Thanks for signing up!</p>',
  },
  {
    from: 'Acme <onboarding@resend.dev>',
    to: ['delivered@resend.dev'],
    subject: 'Order Confirmation',
    html: '<p>Your order has been confirmed.</p>',
  },
]);

console.log(data);

PHP

$resend = Resend::client('re_xxxxxxxxx');

$resend->batch->send([
  [
    'from' => 'Acme <onboarding@resend.dev>',
    'to' => ['delivered@resend.dev'],
    'subject' => 'Welcome to Acme',
    'html' => '<p>Thanks for signing up!</p>',
  ],
  [
    'from' => 'Acme <onboarding@resend.dev>',
    'to' => ['delivered@resend.dev'],
    'subject' => 'Order Confirmation',
    'html' => '<p>Your order has been confirmed.</p>',
  ]
]);

Python

import resend
from typing import List

resend.api_key = "re_xxxxxxxxx"

params: List[resend.Emails.SendParams] = [
  {
    "from": "Acme <onboarding@resend.dev>",
    "to": ["delivered@resend.dev"],
    "subject": "Welcome to Acme",
    "html": "<p>Thanks for signing up!</p>",
  },
  {
    "from": "Acme <onboarding@resend.dev>",
    "to": ["delivered@resend.dev"],
    "subject": "Order Confirmation",
    "html": "<p>Your order has been confirmed.</p>",
  }
]

resend.Batch.send(params)

Ruby

require "resend"

Resend.api_key = 're_xxxxxxxxx'

params = [
  {
    "from": "Acme <onboarding@resend.dev>",
    "to": ["delivered@resend.dev"],
    "subject": "Welcome to Acme",
    "html": "<p>Thanks for signing up!</p>",
  },
  {
    "from": "Acme <onboarding@resend.dev>",
    "to": ["delivered@resend.dev"],
    "subject": "Order Confirmation",
    "html": "<p>Your order has been confirmed.</p>",
  }
]

Resend::Batch.send(params)

package main

import (
	"context"
	"fmt"

	"github.com/resend/resend-go/v4"
)

func main() {
  ctx := context.TODO()
  client := resend.NewClient("re_xxxxxxxxx")

  var batchEmails = []*resend.SendEmailRequest{
    {
      From:    "Acme <onboarding@resend.dev>",
      To:      []string{"delivered@resend.dev"},
      Subject: "Welcome to Acme",
      Html:    "<p>Thanks for signing up!</p>",
    },
    {
      From:    "Acme <onboarding@resend.dev>",
      To:      []string{"delivered@resend.dev"},
      Subject: "Order Confirmation",
      Html:    "<p>Your order has been confirmed.</p>",
    },
  }

  sent, err := client.Batch.SendWithContext(ctx, batchEmails)

  if err != nil {
    panic(err)
  }
  fmt.Println(sent.Data)
}

Rust

use resend_rs::types::CreateEmailBaseOptions;
use resend_rs::{Resend, Result};

#[tokio::main]
async fn main() -> Result<()> {
  let resend = Resend::new("re_xxxxxxxxx");

  let emails = vec![
    CreateEmailBaseOptions::new(
      "Acme <onboarding@resend.dev>",
      vec!["delivered@resend.dev"],
      "Welcome to Acme",
    )
    .with_html("<p>Thanks for signing up!</p>"),
    CreateEmailBaseOptions::new(
      "Acme <onboarding@resend.dev>",
      vec!["delivered@resend.dev"],
      "Order Confirmation",
    )
    .with_html("<p>Your order has been confirmed.</p>"),
  ];

  let _emails = resend.batch.send(emails).await?;

  Ok(())
}

Java

import com.resend.*;
import com.resend.core.exception.ResendException;
import com.resend.services.batch.model.CreateBatchEmailsResponse;
import com.resend.services.emails.model.CreateEmailOptions;
import java.util.Arrays;

public class Main {
    public static void main(String[] args) throws ResendException {
        Resend resend = new Resend("re_xxxxxxxxx");

        CreateEmailOptions firstEmail = CreateEmailOptions.builder()
            .from("Acme <onboarding@resend.dev>")
            .to("delivered@resend.dev")
            .subject("Welcome to Acme")
            .html("<p>Thanks for signing up!</p>")
            .build();

        CreateEmailOptions secondEmail = CreateEmailOptions.builder()
            .from("Acme <onboarding@resend.dev>")
            .to("delivered@resend.dev")
            .subject("Order Confirmation")
            .html("<p>Your order has been confirmed.</p>")
            .build();

        CreateBatchEmailsResponse data = resend.batch().send(
            Arrays.asList(firstEmail, secondEmail)
        );
    }
}

.NET

using Resend;

IResend resend = ResendClient.Create("re_xxxxxxxxx");

var mail1 = new EmailMessage()
{
    From = "Acme <onboarding@resend.dev>",
    To = "delivered@resend.dev",
    Subject = "Welcome to Acme",
    HtmlBody = "<p>Thanks for signing up!</p>",
};

var mail2 = new EmailMessage()
{
    From = "Acme <onboarding@resend.dev>",
    To = "delivered@resend.dev",
    Subject = "Order Confirmation",
    HtmlBody = "<p>Your order has been confirmed.</p>",
};

var resp = await resend.EmailBatchAsync([mail1, mail2]);
Console.WriteLine("Nr Emails={0}", resp.Content.Count);

cURL

curl -X POST 'https://api.resend.com/emails/batch' \
     -H 'Authorization: Bearer re_xxxxxxxxx' \
     -H 'Content-Type: application/json' \
     -d $'[
  {
    "from": "Acme <onboarding@resend.dev>",
    "to": ["delivered@resend.dev"],
    "subject": "Welcome to Acme",
    "html": "<p>Thanks for signing up!</p>"
  },
  {
    "from": "Acme <onboarding@resend.dev>",
    "to": ["delivered@resend.dev"],
    "subject": "Order Confirmation",
    "html": "<p>Your order has been confirmed.</p>"
  }
]'

CLI

resend emails batch --file ./path/to/emails.json

Response format

The batch endpoint returns an array of email IDs for successfully created emails. When the request succeeds, each entry in data corresponds to the email at the same index in the batch payload (0-based). The first email in your request will be the first entry in data, and so on.

JSON

{
  "data": [
    {
      "id": "ae2014de-c168-4c61-8267-70d2662a1ce1"
    },
    {
      "id": "faccb7a5-8a28-4e9a-ac64-8da1cc3bc1cb"
    }
  ]
}

If the request fails, the response will include an error object with a message property. You can find more information about the error in the Errors section of the API Reference.

Limitations

When using batch sending, keep in mind:

Maximum of 100 emails per batch request
The attachments field is not supported yet
Each email in the batch is processed independently
The request will fail and return an error if any email in your payload is invalid (for example, required fields are missing or fields contain invalid data).

View batch emails

All emails sent via the batch endpoint appear in the Emails page of your dashboard along with individually sent emails. Each email will have a queued status initially before being processed.

API Reference

For complete API documentation, see the Send Batch Emails API reference.

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Batch Sending

When to use batch sending

Send batch emails

Response format

Limitations

View batch emails

API Reference

Get started

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Resources