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Send a campaign

Use POST /api/v2/Campaign to send a message to one or more recipients.
Response:
Campaign response

Multiple recipients

Multiple recipients payload
The notifyId field is echoed back in webhooks and DLRs, letting you match every callback to the right record in your system. See notifyId for use cases and full flow examples.

Partial delivery

If a campaign contains a mix of valid and invalid numbers, the valid numbers will still be sent to — the request is not rejected as a whole. Invalid numbers are skipped and reported in the errors array of the response. Always check the response payload to identify any numbers that failed validation.

Recipient limit

A single campaign request supports up to approximately 400,000 recipients. For very large sends, split your audience into batches below this limit.

Schedule for later

Add a sendAt timestamp (UTC) to schedule the campaign:
Scheduled campaign payload

Phone number format

Message length & credits

SMS messages are billed per message part. Understanding how parts work helps avoid unexpected credit usage. Messages longer than 4 parts are not supported.
Long messages are delivered as a single seamless message on the recipient’s device — they will not see separate parts.

Unicode characters

The API supports Unicode, which includes characters outside the standard GSM alphabet — accented characters (é, ü, ñ), non-Latin scripts, and emojis.
Unicode reduces the characters per part. A standard SMS holds 160 GSM characters, but only 70 Unicode characters per part. A short message with a single emoji can consume 2–4 credits.Additionally, some Unicode characters — particularly emojis — may not display correctly on all handsets. For reliable delivery, stick to standard GSM characters where possible.

Sending hours

There are no system-enforced sending hour restrictions. However, you are responsible for adhering to Irish marketing regulations — see Compliance for details.

Limits & billing

There are no rate limits on API calls themselves. Throughput is governed by:
  • Payload size — very large batches may take longer to process
  • Account credits — messages will not be sent if your account has insufficient credit
  • Billing tier — contact support@phonovation.com for details on your account limits
Last modified on July 16, 2026