10DLC (10-Digit Long Code) registration is now mandatory for businesses sending A2P SMS messages in the United States using local phone numbers. Carriers like T-Mobile, AT&T, and Verizon require businesses to register their brand and campaigns through The Campaign Registry (TCR) before sending automated texts. Without registration, your messages face heavy filtering, throttling, or outright blocking.
Phone validation plays a critical role in maintaining 10DLC compliance and maximizing the throughput you’re approved for.
What Is 10DLC?
10DLC is a carrier-mandated system that allows businesses to send A2P (Application-to-Person) SMS messages using standard 10-digit phone numbers. Before 10DLC, businesses often sent automated texts through local numbers without registration — carriers now actively filter unregistered traffic.
The registration process involves two steps:
- Brand registration — Your business identity is verified through TCR
- Campaign registration — Each use case (marketing, 2FA, alerts, etc.) is registered separately with a description and estimated volume
Your approved throughput (messages per second) and daily message limits depend on your trust score, which carriers calculate based on your brand verification and campaign details.
Why Phone Validation Matters for 10DLC
Protect Your Trust Score
Carrier trust scores factor in delivery success rates. High bounce rates from sending to invalid, disconnected, or landline numbers signal poor data quality and can result in reduced throughput or campaign suspension. Validating phone numbers before sending keeps your delivery metrics clean.
Avoid Carrier Filtering
Even with proper 10DLC registration, carriers monitor message delivery patterns. Repeated sends to non-existent numbers or landlines trigger spam detection algorithms. Phone validation eliminates these sends before they happen.
Maximize Throughput
Higher trust scores earn higher throughput limits. By maintaining clean delivery metrics through phone validation, you preserve and potentially increase your approved message rates.
Stay Compliant with Content Rules
10DLC campaigns must match their registered use case. Sending marketing messages under a 2FA campaign registration violates the terms. While phone validation doesn’t directly address content compliance, the line type data helps ensure you’re sending the right type of message to the right type of number — SMS to mobile numbers only, not landlines.
What to Validate Before Sending
For every number in your messaging list, check:
- Line type — Only send SMS to mobile numbers. Landlines can’t receive texts, and many VoIP numbers drop them.
- Deliverability — Confirm the number is active and capable of receiving messages.
- Carrier and porting status — Ensure the message routes to the correct current network.
- Deactivation status — Remove numbers that have been disconnected or suspended.
CheckThatPhone returns all of these fields in a single API call, making it straightforward to validate your lists before every campaign.
Getting Started
10DLC compliance starts with clean data. By validating phone numbers before sending, you protect your trust score, maximize throughput, and avoid the carrier filtering that kills campaign performance. Read the API documentation to integrate phone validation into your messaging workflow, or explore pricing plans to start validating at the volume you need.