1. What is 10DLC?
10DLC means 10 Digit Long Code. It is commonly used to describe business SMS/MMS traffic sent through United States +1 local long code numbers.
2. When it may apply
10DLC requirements may apply when a business sends A2P or B2C traffic using +1 long code numbers to recipients in the United States. Requirements may vary depending on carrier, provider, route, brand, campaign type, volume and use case.
3. Brand registration
Some programs require registering company or Brand information, including legal name, tax identification when applicable, website, industry, address, contact and verification data.
4. Campaign registration
The campaign describes the message use case. It may require a description, categories, message samples, opt-in flow, opt-out information, links to public policies and other compliance data.
5. Assigned numbers
Numbers used to send SMS/MMS may need to be associated with an approved campaign. Sending traffic from unregistered or unassigned numbers may result in blocking, filtering, rejection or limitations.
6. Consent and opt-in
The customer must keep evidence that the recipient authorized receiving messages. The opt-in method must be clear, verifiable and aligned with the type of communication being sent.
7. Opt-out
Messaging programs must honor unsubscribe and opt-out requests. For SMS, words such as STOP or other mechanisms defined by carrier, provider, country or applicable regulation may apply.
8. Visible policies
Some use cases require the company website to display a privacy policy, terms, opt-in/opt-out information and a description of messaging usage.
9. Why it matters
Unregistered, misclassified, abusive, misleading or use-case-inconsistent traffic may be filtered, blocked, rate limited, rejected or subject to carrier/provider enforcement.
10. TelHarbor role
TelHarbor helps customers prepare information, review use cases, document consent flows, configure numbers and coordinate messaging requirements based on provider, carrier, route and selected service.
11. External references
The following resources are general external references. Requirements may change and should be validated according to provider, carrier, route and use case.
- The Campaign Registry
- CTIA Messaging Principles and Best Practices
- Provider reference: Twilio A2P 10DLC
- Provider reference: Telnyx 10DLC FAQ
Note: This page is informational and does not replace legal, regulatory, provider, carrier or industry guidance.
Last updated: 2026-06-15