Batch Send

Request body

An array of up to 100 email objects. Each object has the same schema as POST /emails, except that attachments and scheduled_at are not supported here — send or schedule those individually via POST /emails.

curl -X POST https://api.eusend.dev/emails/batch \
  -H "Authorization: Bearer eu_live_xxxxxxxxxxxx" \
  -H "Content-Type: application/json" \
  -d '[
    {
      "from": "noreply@acme.com",
      "to": "alice@example.com",
      "subject": "Receipt #1001",
      "html": "<p>Thanks, Alice!</p>",
      "tags": { "category": "receipt" }
    },
    {
      "from": "noreply@acme.com",
      "to": "bob@example.com",
      "subject": "Receipt #1002",
      "html": "<p>Thanks, Bob!</p>"
    }
  ]'

Response

One result per input email, in the same order: data[i] describes emails[i]. A queued email carries its id; an email that could not be queued carries error and code instead (for example an unverified sender domain, all recipients suppressed, or an exhausted quota). Failed items never fail the rest of the batch — retry just those.

{
  "data": [
    { "id": "9a8b7c6d-5e4f-4a3b-8c1d-0e9f8a7b6c5d" },
    { "error": "All recipients are suppressed", "code": "ALL_SUPPRESSED" }
  ]
}

Idempotency

Pass an Idempotency-Key header to make a retried batch safe. Each item is tracked under the key and its position, so resending the same batch returns the ids of the emails that were already queued — without sending them again — and processes only the items that failed or never ran. Keep the items in the same order when you retry. A batch whose items were all queued before answers 200 OK with the original ids.