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Deliverability is the percentage of your sent messages that actually reach the recipient’s handset. This section covers the factors that affect it and what you can do about them.

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T-Mobile volume caps

T-Mobile enforces daily volume caps per campaign based on the volume tier you registered: Messages that exceed the cap are queued or filtered, not delivered. If you need to send more than 2,000 segments per day to T-Mobile, register your campaign at high volume. “SMS segments” are the carrier billing unit, not messages. A single message with 200 characters costs 2 segments (161–306 characters in GSM-7). See SMS Segments & Encoding.

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Surge’s content policy layer

Surge runs a content-policy check on outbound messages before they reach the carrier. This catches links, patterns, and content that carriers commonly filter — before the message is sent and marked as failed. If your message is blocked by the content policy, you’ll see a message_filtered error in the message.failed webhook event. Common reasons:
  • Unregistered link shorteners. Third-party link shorteners (bit.ly, tinyurl.com, etc.) are frequently flagged by carrier spam filters. Surge’s built-in link shortening will have better results, but for the best results use your own branded domain.
  • Content not matching your campaign. If your campaign is registered for customer_care but your messages contain marketing language and promotional links, the content mismatch will be flagged.
  • Age-gated or lending content without the flag. If your messages contain age-gated content or direct lending references but you didn’t include age_gated or direct_lending in your campaign’s includes array, those messages will be filtered.

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The includes flags

The includes array in your campaign registration tells carriers what content types your messages contain. Being accurate here directly affects deliverability: Missing a flag when the content is present is a deliverability problem, not just a registration problem. Carriers can filter messages that don’t match the registered content profile. See Canonical Schema Reference for the full list of valid includes values and their descriptions.

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Carrier fees

Carriers charge per-message fees that vary by destination network. These fees are passed through in your Surge billing and visible in your usage reports. Carriers sometimes give discounts as a charity campaign.

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Monitoring deliverability

Watch the message.delivered and message.failed webhook events. A sustained spike in message.failed events with message_filtered as the reason is a signal to review your content against your campaign registration. Blast-level delivery metrics (aggregate deliverability rate, opt-out rate per send) are available in the dashboard under Blasts.