Sending

Batch sending

Send up to 100 emails in one request with POST /emails/batch, with all-or-nothing validation and one rate-limit token.

POST /emails/batch sends up to 100 different emails in one request. It is the efficient way to send many messages, because the whole batch uses a single request against your rate limit.

This endpoint works with a sending_access key.

Request

The body is a JSON array. Each element accepts the same fields as POST /emails, with the exceptions listed below.

Shell

curl -X POST https://api.sooner.dev/emails/batch \
  -H "Authorization: Bearer $SOONER_API_KEY" \
  -H "Content-Type: application/json" \
  -H "Idempotency-Key: digest-2026-11-14" \
  -d '[
    {
      "from": "Acme <hello@mail.yourcompany.com>",
      "to": ["ada@example.com"],
      "subject": "Your weekly digest",
      "html": "<p>Hi Ada, here is your digest.</p>"
    },
    {
      "from": "Acme <hello@mail.yourcompany.com>",
      "to": ["grace@example.com"],
      "subject": "Your weekly digest",
      "html": "<p>Hi Grace, here is your digest.</p>"
    }
  ]'

JSON

{
  "data": [
    { "id": "01jcz8w3f2x9k4m7n6p5q2r1s0" },
    { "id": "01jcz8w3f2z1h6c8d4e2f9g7t3" }
  ]
}

The IDs are in the same order as the emails in your request.

With the Node SDK:

TypeScript

const { data, error } = await resend.batch.send([
  {
    from: "Acme <hello@mail.yourcompany.com>",
    to: ["ada@example.com"],
    subject: "Your weekly digest",
    html: "<p>Hi Ada, here is your digest.</p>",
  },
  {
    from: "Acme <hello@mail.yourcompany.com>",
    to: ["grace@example.com"],
    subject: "Your weekly digest",
    html: "<p>Hi Grace, here is your digest.</p>",
  },
]);

Rules

Rule	Detail
Size	1 to 100 emails per request.
Attachments	Not allowed. A batch with any `attachments` is rejected.
Scheduling	Not allowed. A batch with any `scheduled_at` is rejected.
Templates	Allowed. Each email can use its own `template`.
Validation	All or nothing. If one email is invalid, nothing is queued and no quota is used. The error message names the position, for example `(email 3)`, counting from 0.
Quota	A batch of N emails counts as N against your monthly quota, and against the daily cap on Free. If the batch would cross a cap, the whole request is rejected.
Idempotency	The `Idempotency-Key` header covers the whole batch. A retry returns the same list of IDs.
Recipients	Each email has its own limit of 50 recipients across `to`, `cc` and `bcc`.

Each email in a batch is processed independently after it is accepted. One recipient bouncing does not affect the others, and each email has its own ID, status and events.

Errors

A batch can fail with any of the errors in Send an email. The most common for batches:

JSON

{
  "statusCode": 422,
  "message": "Batch emails can't have attachments or scheduled_at.",
  "name": "validation_error"
}

Use a batch when you have many emails to send at once, such as a digest or a notification fan-out. For a message to a large audience from a segment, with unsubscribe handling, use broadcasts.