A2P 10DLC registration, TCPA requirements, carrier filtering, and SMS deliverability. Everything you need to stay compliant and keep messages landing in inbox.
Get a Free Compliance AuditA2P 10DLC is the US carrier framework governing all business SMS sent on 10-digit long codes. AT&T, Verizon, and T-Mobile enforce it without exception. Without brand and campaign registration through The Campaign Registry, carrier filtering can block 30% or more of your outbound messages - with no error code to explain the drop. Twilio returns error 30007 for carrier-blocked messages, which is often the first sign a business gets that its SMS program is failing.
Registration isn't technically complex, but it's unforgiving of errors. A business name on your TCR submission that doesn't exactly match your EIN filing delays approval by weeks. Selecting the wrong campaign use case - "Customer Care" when carriers classify your messages as "Marketing" - triggers a rejection, a $15 re-registration fee, and another review cycle that can run 2–4 weeks at AT&T alone.
TCPA compliance adds a separate layer of risk. The Telephone Consumer Protection Act requires prior express written consent before sending marketing SMS to any US mobile number. Violations carry statutory damages of $500 per message for negligent violations and $1,500 per message for willful violations - with no cap on class action exposure. A campaign sent to 50,000 unconsented recipients creates potential liability of $25 million to $75 million before litigation costs are counted.
The 30 guides below cover every compliance challenge Twilio users face: A2P 10DLC registration and rejection fixes, toll-free verification, TCPA-compliant opt-in flows, GDPR requirements for EU recipients, carrier content filters, sender reputation management, and SPF/DKIM/DMARC configuration for SendGrid email. All guides reflect carrier policies and regulatory requirements current as of June 2026.
A2P 10DLC is the mandatory framework governing business SMS on 10-digit long codes in the US. Without registration, carrier filtering can block up to 30% of your messages without any warning.
Brand registration is the first mandatory step in the A2P 10DLC process. Getting the details wrong here delays your entire campaign approval by weeks and triggers manual vetting reviews.
Campaign registration tells carriers exactly what kind of messages you plan to send and how recipients consented. The quality of your submission directly determines your approval odds and throughput score.
Choosing the wrong A2P 10DLC registration track caps your throughput and leaves you exposed to filtering. Here is exactly when to use Sole Proprietor and when to register as a Standard brand.
A2P 10DLC approval is not instant. Timelines differ by carrier and registration quality, and AT&T manual review alone can take two to four weeks. Plan your SMS launch schedule accordingly.
Campaign rejections halt your SMS program entirely until you resolve them. Most rejections fall into a handful of predictable categories that have clear fixes if you know what to look for.
Toll-free numbers used for SMS now require verification with the carrier before messages can be delivered at full throughput. This guide walks through the Twilio verification process from start to finish.
Toll-free SMS is no longer a compliance-free alternative to 10DLC. Carriers began blocking unverified toll-free traffic in 2023 and enforcement has only tightened through 2026.
Deliverability on Twilio SMS is not just about registration. List hygiene, content quality, sending patterns, and opt-in quality all influence whether your messages reach the intended recipient.
Carrier filtering is the silent killer of SMS campaigns. Understanding exactly what triggers it and how to avoid those triggers is essential for any business sending messages at scale on Twilio.
TCPA violations carry fines of $500 to $1,500 per text message. Understanding exactly what consent is required before you send is non-negotiable for any US SMS program.
A compliant SMS opt-in flow captures verifiable consent, stores it with a timestamped record, and gives subscribers a clear expectation of what they are agreeing to receive. Here is how to build one.
Mishandling opt-out keywords is both a TCPA violation and an A2P 10DLC policy breach. Carriers require that STOP, HELP, and CANCEL keywords produce specific responses and are processed immediately.
GDPR applies to SMS marketing sent to EU residents regardless of where your business is based. The consent standard is stricter than TCPA and penalties reach 4% of global annual turnover.
The Twilio Trust Hub is the central compliance interface for A2P 10DLC registration, toll-free verification, and regulatory compliance. Understanding how it works is essential for managing your SMS program.
Your A2P 10DLC trust score determines your SMS throughput limits and baseline carrier treatment. A score below 50 severely restricts your program before you send a single message.
International SMS compliance is not a single standard. Each country has its own consent requirements, sender ID rules, content restrictions, and registration systems that apply to every message you send.
WhatsApp Business through Twilio has strict content policies, template pre-approval requirements, and a 24-hour messaging window that fundamentally differ from SMS. Violations can result in account suspension.
Using SendGrid through Twilio does not automatically make your emails compliant with CAN-SPAM, CASL, or GDPR. Understanding what these laws require and how SendGrid helps you comply is essential.
SPF, DKIM, and DMARC are the three authentication layers that protect your sending domain and improve deliverability. Without them, your SendGrid emails land in spam and your domain is open to spoofing.
A new phone number with no sending history is treated with suspicion by carrier filtering systems. Warming it up gradually over one to two weeks establishes a clean behavioral baseline that protects your deliverability.
Error code 30007 from Twilio means a carrier blocked your message at the network level. It is a serious signal that requires immediate investigation and can permanently damage your sending reputation if ignored.
Carrier content filters evaluate every message you send. Writing messages that pass those filters while still being effective marketing requires understanding exactly what signals trigger filtering.
Your SMS sender reputation is a composite score built from complaint rates, opt-out rates, bounce rates, and behavioral signals. Once damaged, it takes weeks to repair and directly reduces the revenue your SMS program generates.
Sending SMS from unregistered 10DLC numbers is not just a compliance risk. Carriers actively filter up to 30% of unregistered traffic, and Twilio has begun applying surcharges to unregistered messages.
A quarterly compliance audit of your Twilio account catches registration gaps, expired verifications, misconfigured opt-out handling, and content policy violations before they cause deliverability or legal problems.
STIR/SHAKEN call authentication and branded calling display are transforming how voice calls are verified and presented to recipients. Twilio supports both, and implementing them increases answer rates significantly.
An opt-out rate above 2% per campaign is a signal that your SMS program has a structural problem. Reducing it requires looking at frequency, content relevance, timing, and subscriber expectations.
In TCPA litigation, the burden of proving consent falls on the sender. If you cannot produce a consent record for a specific subscriber on a specific date, you have no defense against a per-message fine of up to $1,500.
Every country where you send SMS has its own carrier rules, registration requirements, and consent standards. This checklist covers the most common destination markets for Twilio senders and what is required in each.
Quick answers to the questions our consultants get asked most often.
A2P 10DLC (Application-to-Person 10-Digit Long Code) is the mandatory US carrier framework for business SMS sent on standard 10-digit phone numbers. Every major US carrier - AT&T, Verizon, T-Mobile - requires brand and campaign registration through The Campaign Registry before delivering your messages at full throughput. Without registration, carrier filtering can block 30% or more of your outbound messages with no error code explaining the drop. Any business sending SMS on Twilio 10-digit numbers in the US needs A2P 10DLC registration.
Standard brand registration through Twilio's Trust Hub typically takes 1–3 business days for approval. Campaign registration takes an additional 1–5 days for most carriers, but AT&T's manual review process can take 2–4 weeks for standard campaigns. Total timeline from submission to full throughput is usually 2–5 weeks for standard registrations. Sole Proprietor registrations (for individuals without an EIN) approve faster - typically 24–48 hours - but are capped at lower throughput limits.
The Telephone Consumer Protection Act (TCPA) imposes statutory damages of $500 per text message for negligent violations and $1,500 per message for willful violations. There is no cap on class action exposure. A single marketing campaign sent to 50,000 recipients without proper prior express written consent creates potential liability of $25 million to $75 million before litigation costs. The FCC actively enforces TCPA, and private class action suits are common. Consent records must be retained and producible on demand.
Carrier filtering is triggered by a combination of signals: sending from unregistered 10DLC numbers, URLs in messages (especially URL shorteners), high opt-out rates above 1–2%, message content resembling known spam patterns (urgency language, excessive capitalization, misleading sender identity), volume spikes above your registered throughput, and high bounce rates from invalid numbers. Error code 30007 in Twilio indicates a carrier-level block. Warming new numbers gradually over 1–2 weeks and maintaining list hygiene prevents most filtering issues.
Yes. Toll-free SMS verification became mandatory in 2023 and enforcement has tightened through 2024 and 2025. Unverified toll-free numbers face carrier filtering similar to unregistered 10DLC numbers. Verification requires submitting use case documentation, opt-in flow details, and sample messages through Twilio for carrier review. Approval takes 2–4 weeks. Verified toll-free numbers support throughput of up to 3 SMS segments per second - lower than registered long codes - and can receive both calls and texts on the same number.
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