Xurel Docs

Idempotency

Safely retry sends without creating duplicate messages by sending an Idempotency-Key header.

Supported endpoints

  • POST /emails
  • POST /emails/batch

Header: Idempotency-Key: <string max 256>

Behavior

  • Window: 24 hours per API key / tenant.
  • Same key + same body → original response is replayed.
  • Same key + different body → 409 idempotency_conflict.
  • For batch, the key applies to the whole batch request, not per item.

Example

cURL 
curl https://api.xurel.co/v1/emails \
  -H "Authorization: Bearer $XUREL_API_KEY" \
  -H "Content-Type: application/json" \
  -H "Idempotency-Key: order-42-receipt" \
  -d '{"from":"billing@yourdomain.com","to":["user@example.com"],"subject":"Receipt","html":"<p>Thanks</p>","type":"transactional"}'