What Is 10DLC?

10DLC (10-Digit Long Code) is the carrier-mandated registration system for sending application-to-person (A2P) SMS and MMS over standard local phone numbers in the United States. Every business that sends text messages through a local 10-digit number must register a brand and at least one campaign with The Campaign Registry (TCR) before messages will be delivered at full throughput --- or delivered at all.

The system exists because carriers needed a way to distinguish legitimate business messaging from spam without resorting to the blunt filtering that plagued the industry for years.

Why 10DLC Exists

The Pre-2019 Problem

Before 10DLC, there was no formal registration channel for businesses sending A2P traffic over local numbers. The only sanctioned A2P sender types were short codes (expensive, slow to provision) and toll-free numbers (limited to transactional use in practice). Businesses that wanted affordable, high-volume messaging had two options: pay $1,000+/month for a short code or send traffic over local long codes with no registration --- a practice carriers tolerated but never officially endorsed.

This gray area created serious problems:

• Spam flourished. Bad actors exploited unregistered long codes to blast millions of messages with no accountability trail.
• Carriers over-filtered. Without registration data, carriers could not distinguish a pharmacy sending appointment reminders from a spammer pushing payday loans. The result was aggressive content filtering that blocked legitimate messages alongside spam.
• Deliverability was unpredictable. A message that delivered fine on Tuesday might be silently dropped on Wednesday after a carrier updated its filtering rules.
• Throughput was throttled. Carriers limited unregistered long codes to roughly 1 message per second --- a rate that made time-sensitive campaigns impractical.

The Industry Response

In 2019, the major U.S. mobile network operators (MNOs) --- AT&T, T-Mobile, and Verizon --- backed the creation of The Campaign Registry (TCR) as a centralized registration system. The deal was straightforward: businesses identify themselves and describe their messaging use cases, and in return, carriers grant higher throughput and more predictable delivery. By 2021, carriers began requiring registration and imposing per-message surcharges. By early 2025, registration became mandatory --- unregistered long code A2P traffic is blocked outright.

The TCR Ecosystem

10DLC registration involves four types of entities working together:

The Campaign Registry (TCR)

TCR is the central database. It stores brand identities, campaign metadata, trust scores, and registration status. TCR does not route messages or interact with end users. It is a registry, not a messaging platform.

Communication Service Providers (CSPs)

CSPs are the platforms businesses use to send messages --- companies like Twilio, Bandwidth, Telnyx, Sinch, Vonage, and Plivo. CSPs integrate directly with TCR and submit registrations on behalf of their customers. Most businesses interact with the 10DLC system exclusively through their CSP's dashboard or API.

Direct Connect Aggregators (DCAs)

DCAs sit between CSPs and carriers, handling the actual message routing and carrier connectivity. Syniverse and Iconectiv are the primary DCAs in the 10DLC ecosystem. They propagate campaign registration data from TCR to the carrier networks and enforce compliance at the routing layer.

Mobile Network Operators (MNOs)

The three major U.S. carriers --- AT&T, T-Mobile, and Verizon --- are the enforcement layer. They set throughput limits based on trust scores, apply per-message surcharges, and ultimately decide whether a message is delivered, filtered, or blocked.

Brand Registration

Brand registration is the first step. It establishes the identity of the business sending messages.

What Is Required

• Legal business name as registered with the IRS
• EIN (Employer Identification Number) for standard businesses, or SSN for sole proprietors
• Business address matching IRS records
• Business website (strongly recommended; absence lowers trust scores)
• Business type: sole proprietorship, LLC, corporation, partnership, non-profit, or government
• Industry vertical: healthcare, finance, retail, education, etc.

Vetting and Fees

Brand registration involves two cost components:

The $4 registration fee covers basic EIN/identity verification. For higher trust scores and increased throughput, businesses can opt into external vetting (also called enhanced vetting) through third-party providers. External vetting performs deeper checks: business credit, legal standing, operational history, and web presence validation.

External vetting is optional for most use cases but effectively required for any campaign that needs more than baseline throughput.

Sole Proprietor vs. Standard Registration

Sole proprietors face a more restrictive registration path:

Sole proprietor brands are capped at the lowest trust tier regardless of messaging behavior. Businesses that need meaningful throughput should register as a standard brand with an EIN.

Campaign Registration

After brand registration, each distinct messaging use case requires its own campaign registration.

Use Case Categories

TCR defines standard use case types. Each campaign must be mapped to one:

Mixed campaigns receive lower trust scores than single-purpose campaigns. Splitting distinct use cases into separate campaigns generally yields better throughput.

Required Campaign Details

Each campaign submission includes:

• Sample messages (at least 2): real examples of what the recipient will receive
• Opt-in description: how users consent to receive messages (web form, keyword text, point-of-sale, etc.)
• Opt-in keywords: typically "START", "YES", or "SUBSCRIBE"
• Opt-out keywords: must include "STOP" at minimum
• Help keywords: typically "HELP"
• Message flow description: a narrative explaining the end-to-end messaging experience
• Embedded links: whether messages contain URLs (affects filtering scrutiny)
• Embedded phone numbers: whether messages reference other phone numbers
• Age-gated content: whether content requires age verification

Campaign Approval

TCR reviews campaigns for CTIA guideline compliance. Key criteria: sample messages must match the declared use case, opt-in flow must demonstrate explicit prior consent, content must not fall into restricted SHAFT categories (sex, hate, alcohol, firearms, tobacco), and the brand's website must corroborate the use case.

Approval typically takes 1--5 business days, though some campaigns clear within hours. Carriers may independently reject or suspend campaigns even after TCR approval.

Trust Scores and Throughput

The core value proposition of 10DLC is this: registered campaigns get higher message throughput. The amount of throughput depends on the trust score, a numeric rating TCR assigns based on brand and campaign attributes.

How Trust Scores Work

Trust scores are calculated from multiple factors:

• Brand age and history: longer-established businesses score higher
• External vetting result: the single biggest factor for score improvement
• Business type: publicly traded companies and government entities receive high baseline scores
• Website quality: a functioning, professional website with clear business information
• Industry vertical: some industries receive closer scrutiny
• Campaign use case: single-purpose campaigns (especially OTP and transactional) score higher than mixed
• Prior violations: any history of carrier violations or spam complaints reduces scores

Throughput Limits by Trust Score

Throughput is measured in messages per second (MPS) and varies by carrier. The following table shows approximate AT&T throughput tiers, which are representative of the general structure:

These numbers shift as carriers update policies. T-Mobile additionally enforces daily message caps on lower tiers. AT&T bases limits purely on per-second throughput. Verizon's limits are generally aligned with AT&T's structure.

Campaigns with external vetting typically land in the medium-high to high tiers. Without vetting, most campaigns plateau at the medium tier.

Carrier Pass-Through Fees

All three major carriers impose per-message surcharges on 10DLC traffic. These fees are passed through by CSPs to the sending business on top of the CSP's own per-message pricing.

These rates are approximate and subject to change. Some carriers apply tiered pricing based on campaign type (lower for transactional, higher for marketing). CSPs may add their own markup. Inbound messages (mobile-originated) do not incur 10DLC surcharges --- fees apply only to outbound A2P traffic.

Enforcement Timeline

The path to mandatory 10DLC registration unfolded over several years:

As of February 2025, sending A2P messages over an unregistered 10-digit long code on any major U.S. carrier network will result in message blocking. There is no grace period or soft-fail mode.

Common Rejection Reasons

Campaign registrations are rejected more often than most businesses expect. Here are the most frequent causes and how to address them:

Brand Rejections

Campaign Rejections

After Rejection

Rejected campaigns can be resubmitted after corrections, typically with no additional fee. Review the specific rejection reason from TCR, correct the issue, and resubmit --- do not resubmit without changes, as repeated identical submissions may trigger additional scrutiny.

Key Takeaways

• 10DLC registration is mandatory for any business sending A2P SMS over local U.S. phone numbers.
• Brand + campaign registration through TCR is required before sending. The process costs roughly $4--$44 depending on whether external vetting is included.
• Trust scores determine throughput. External vetting is the most effective way to increase scores and unlock higher message-per-second limits.
• Carrier surcharges apply on every outbound message, adding ~$0.003--$0.005 per segment on top of CSP pricing.
• Sole proprietors are heavily restricted in throughput and campaign count. Standard brand registration with an EIN is strongly recommended.
• Campaign specificity matters. Single-purpose campaigns score higher than mixed-use campaigns.

Further Reading

• Short Code vs 10DLC vs Toll-Free --- comparing SMS sender types by cost, throughput, and registration requirements
• Carrier SMS Filtering --- how AT&T, Verizon, and T-Mobile analyze and filter A2P traffic