Schedule Email

Additional parameter

• scheduled_atstringoptionalnew

  When to send the email. Accepts ISO 8601 format or natural language. Must be in the future.

  e.g. "in 1 hour" · "tomorrow at 9am" · "2026-08-05T11:52:01Z"

All other parameters are identical to Send Email.

Natural language

Any of these formats works for scheduled_at.

• "in 1 hour"
• "in 30 minutes"
• "tomorrow at 9am"
• "Friday at 3pm ET"
• "next Monday at 8am"
• "2026-08-05T11:52:01Z"

Quick start

import axios from 'axios';

const response = await axios.post(
  'https://mail.sendcorex.com/v3.0/send',
  {
    to: 'user@example.com',
    from: 'noreply@yourdomain.com',
    senderName: 'My App',
    subject: 'Your weekly digest',
    body: '<p>Here is what happened this week...</p>',
    scheduled_at: 'tomorrow at 9am',
  },
  { headers: { Authorization: process.env.SENDCOREX_API_KEY } }
);

// Save the id: you need it to cancel the email before it is sent
const { id, ids, scheduledAt, recipients } = response.data;
console.log('Scheduled for ' + scheduledAt + ' (id: ' + id + ')');

Response

{
  "success": true,
  "message": "Email scheduled successfully",
  "code": "EMAIL_SCHEDULED_SUCCESS",
  "id": "3f2a1b4c-8e9d-4f7a-b2c3-1a2b3c4d5e6f",
  "ids": [
    { "id": "3f2a1b4c-8e9d-4f7a-b2c3-1a2b3c4d5e6f", "recipient": "user@example.com" }
  ],
  "scheduledAt": "2026-04-26T09:00:00.000Z",
  "recipients": 1
}

Errors return a JSON object with error and code.

• 401MISSING_AUTH_HEADER

  No Authorization header present.

• 401INVALID_API_KEY

  The API key is invalid or revoked.

• 401ACCOUNT_BLOCKED

  Account has been blocked.

• 401NO_CREDITS_LEFT

  No email credits remaining.

• 401DOMAIN_NOT_VALIDATED

  Sender domain not verified.

• 401LISTED_SPAM_HAUS

  Sender domain is listed on Spamhaus.

• 401ISP_DOMAIN_BLOCKED

  Sending from well-known domains (gmail.com, outlook.com, etc) is not allowed.

• 401FROM_HEADER_DOMAIN_MISMATCH

  From header domain not authorized for this sender.

• 401USER_NOT_FOUND

  User not found.

• 401MISSING_USER_PRIVILEGES

  Missing user privileges.

• 401EMAIL_CREDITS_NOT_FOUND

  Error fetching email credits.

• 429CREDENTIAL_TEMPORARILY_BLOCKED

  API key temporarily blocked due to repeated policy violations.

• 429IP_TEMPORARILY_BLOCKED

  Requesting IP temporarily blocked due to repeated policy violations.

• 400MISSING_FROM

  The from field is missing or empty.

• 400INVALID_FROM_FORMAT

  The from field must be a valid email address.

• 400MISSING_SENDERNAME

  The senderName field is missing or empty.

• 400INVALID_SENDERNAME_FORMAT

  The senderName field contains invalid characters.

• 400MISSING_SUBJECT

  The subject field is missing or empty.

• 400MISSING_BODY

  The body field is missing or empty.

• 400MISSING_TOADDRESS

  The to field is missing or empty.

• 400MISSING_TO

  The to field is missing or empty.

• 400INVALID_TOADDRESS

  One or more recipient addresses are malformed.

• 400TOADDRESS_LIMIT_EXCEEDED

  More than 50 recipients in the to array.

• 400INVALID_SCHEDULED_AT

  scheduled_at is not a valid date or is in the past.

• 400INVALID_SENDER_FORMAT

  The sender email format is invalid.

• 400HEADER_NOT_ALLOWED

  Custom header key is not on the allowed list (List-Unsubscribe, List-Id, X-*, etc).

• 400INVALID_HEADER_VALUE

  Header value contains invalid characters (CR/LF not allowed).

• 400DANGEROUS_ATTACHMENT

  One or more attachments were blocked for security reasons.

• 403ACCOUNT_RESTRICTED

  Account is temporarily restricted.

• 403DAILY_LIMIT

  Daily email sending limit reached.

• 403SPAM_DETECTED

  Email content flagged as spam. Response includes quarantine_id and release instructions.

• 403SENDER_NAME_MISMATCH

  Multiple sender names detected for same address.

• 403FOLLOWUP_PATTERN_DETECTED

  Email content flagged as repeated suspicious follow-up pattern.

• 403SCAM_PATTERN_DETECTED

  Email content flagged as scam pattern.

• 403ACCOUNT_SUSPENDED_SPOOFING

  Account suspended due to repeated From header spoofing attempts.

• 500INTERNAL_SERVER_ERROR

  Unexpected server error. Try again.

• 500PARSE_ERROR

  Failed to process email content (MIME parse failure).

• 500PERSIST_FAILED

  Failed to queue email (database persistence failure).