Text messaging. From your carrier.

Yes. SIPNEX DIDs support both voice and messaging on the same number. Your outbound SIP trunk handles voice calls and your messaging configuration handles SMS/MMS — same DID, no separate number needed. When a customer receives a text from you and calls back, the call arrives on your SIP trunk.

Yes, for sending business SMS from standard 10-digit numbers. All major US carriers require A2P 10DLC registration through The Campaign Registry. SIPNEX handles the registration on your behalf — you provide business information and campaign details, we submit the brand and campaign registrations and link your numbers.

T-Mobile, AT&T, and Verizon each add per-message surcharges on A2P 10DLC traffic. These are carrier-imposed fees that all messaging providers must collect — approximately $0.003 per SMS and $0.005-$0.01 per MMS depending on the carrier. SIPNEX itemizes surcharges separately on your invoice so you see exactly what you pay to us versus what passes through to carriers.

SMS (Short Message Service) is text-only, 160 characters per segment, $0.005-$0.02 per segment. MMS (Multimedia Messaging Service) supports images, video, and longer text up to 500KB-1MB, $0.015-$0.05 per message. Use SMS for transactional messages and short notifications. Use MMS for marketing with images. See our SMS vs MMS blog post for the full comparison.

SMS delivery is typically under 5 seconds for domestic messages. MMS takes slightly longer (10-30 seconds) due to media processing. Delivery speed also depends on your A2P 10DLC throughput tier — registered campaigns with high trust scores receive higher messages-per-second throughput.

SIPNEX processes STOP responses automatically. When a recipient replies STOP to your message, the number is flagged and future messages to that number are blocked. You receive notification of the opt-out. Carriers monitor opt-out compliance — failing to honor STOP can result in campaign suspension.

Yes, within your A2P 10DLC throughput limits. Throughput depends on your TCR trust score — established businesses with verified EINs typically receive sufficient throughput for marketing campaigns. For very high-volume messaging (100K+ messages), contact us about throughput optimization and campaign structure.

SMS: $0.005-$0.02 per segment. MMS: $0.015-$0.05 per message. Plus carrier surcharges ($0.003-$0.01 per message). Plus A2P registration fees ($4 brand + $10-$15 per campaign, one-time). See our pricing page for current rates. No platform fees, no monthly minimums.