10DLC (10-Digit Long Code) is the standard for business SMS in the US. It requires registration with carriers to verify business identity and use case. 10DLC registration process: - Brand registration (business verification) - Campaign registration (describe use case) - Carrier approval - Ongoing compliance Benefits of 10DLC: - Higher throughput than unregistered numbers - Better deliverability - Local phone number presence - Cost-effective for most use cases Throughput limits: - Unregistered: ~1 SMS/second - Low-volume registered: ~7.5 SMS/second - High-volume registered: ~75+ SMS/second