A2P 10DLC SMS Compliance for Zapier Automation with Twilio and Other SMS Apps

A practical field guide from Automation Ace.

A2P 10DLC SMS Compliance for Zapier Automation with Twilio and Other SMS Apps

If your Zapier automations send SMS or MMS messages through Twilio, Vonage, Bandwidth, or another SMS provider using US long-code phone numbers, A2P 10DLC compliance is not optional — it is a carrier-mandated requirement that affects message deliverability, throughput limits, and the continued operation of any business SMS workflow. This article explains what A2P 10DLC is, why US carriers require it, how it specifically affects Zapier-driven SMS automation, and what registration looks like in practice.

What Is A2P 10DLC?

A2P stands for Application-to-Person — meaning messages sent programmatically by a software application to a human recipient, as opposed to P2P (Person-to-Person) messaging between two individuals. 10DLC stands for 10-Digit Long Code — the standard US local phone number format (e.g., 555-867-5309), as distinct from short codes (5–6 digit numbers used for high-volume campaigns) or toll-free numbers.

The A2P 10DLC registration system was introduced by US mobile carriers (AT&T, T-Mobile, Verizon, and others) as a response to SMS spam and fraud. Previously, businesses could send application-generated messages from standard long-code numbers without registration or oversight, and carriers had limited ability to distinguish legitimate business messaging from spam. The A2P 10DLC framework requires businesses to register their brand and the specific messaging campaigns they run, so carriers can verify legitimate use, enforce message content policies, and improve deliverability for registered senders.

Why This Matters for Zapier SMS Automation

Any Zapier workflow that sends SMS or MMS to US recipients via a long-code number is subject to A2P 10DLC requirements — regardless of whether the automation is built in Zapier. The registration requirement lives at the phone number and messaging provider level, not at the Zapier level. Zapier is simply the orchestration layer that triggers the message send; the actual message transmission goes through your SMS provider (Twilio, Vonage, etc.), and it is through that provider that registration occurs.

Common Zapier SMS workflows affected by A2P 10DLC:

• Lead notification SMS when a form is submitted or a CRM deal is created
• Appointment reminder SMS triggered by a calendar event
• Order confirmation or shipping update SMS from an e-commerce trigger
• Internal alert SMS to a team member when a critical event occurs
• Two-factor authentication or verification code delivery

If the long-code number sending these messages is not registered under A2P 10DLC, carriers may filter or block the messages, reduce throughput (messages per second), or in some cases suspend the number's ability to send application-generated messages entirely.

Registration: Brand and Campaign

A2P 10DLC registration has two components that must both be completed with your SMS provider:

1. Brand registration: You register your business entity — legal business name, EIN (or equivalent tax ID), business type, address, and vertical (industry category). The brand registration establishes who is sending messages.
2. Campaign registration: You register the specific use case — what messages you are sending, to whom, and for what purpose. Each distinct messaging use case (marketing, alerts, two-factor auth, customer care, etc.) requires its own campaign registration, which is tied to the specific phone number(s) used for that use case.

Registration is done through your SMS provider — not directly with the carriers. Twilio's registration process is handled through the Twilio Console under Messaging > Regulatory Compliance. Vonage (now Vonage APIs, part of Ericsson) handles it through their dashboard. Other providers have their own registration flows, but all route to the same carrier registry (TCR — The Campaign Registry).

Twilio and Zapier: Registration Steps

For Zapier automations using Twilio for SMS:

1. Log into your Twilio account and navigate to the Messaging section.
2. Complete Brand registration under Regulatory Compliance — this requires your business EIN and may involve a vetting fee for standard brand registration.
3. Create a Campaign tied to your registered brand, specifying the use case (e.g., notifications, marketing, two-factor auth). Provide sample message content that accurately represents what your Zapier automation will send.
4. Assign the campaign to the specific Twilio phone number(s) used in your Zapier actions. Only registered numbers with assigned campaigns can send A2P messages without carrier filtering.
5. Allow time for carrier approval — brand approval is typically automated, campaign approval may take 1–5 business days depending on use case and carrier.

The Twilio Messaging Action in Zapier passes message content and recipient numbers to Twilio's API. The A2P registration on the sending number determines how carriers handle those messages downstream — Zapier itself has no involvement in the registration process.

Number Types and Compliance Options

A2P 10DLC applies specifically to US standard long-code numbers (10-digit local numbers). Alternatives that have different registration requirements:

• Short codes: 5–6 digit numbers with a separate, more involved carrier approval process. High throughput, expensive, best for very high-volume campaigns.
• Toll-free numbers: 1-800/888/etc. numbers. Also have their own toll-free verification process for A2P use but are distinct from 10DLC. Often used for customer-facing alerts and notifications at moderate volume.
• International numbers: Not subject to US A2P 10DLC requirements but subject to local regulations in the destination country.

If you built a Zapier SMS automation before 2022 using a Twilio long-code number and it worked without registration, that does not mean it will continue to work indefinitely. Carriers have progressively tightened enforcement. An unregistered number sending application-generated messages is increasingly likely to see message filtering rather than delivery.

What Happens Without Registration

Unregistered A2P traffic on long-code numbers faces: reduced throughput (limited to 1 message per second vs. much higher rates for registered numbers), increased likelihood of carrier filtering (messages silently not delivered), risk of number suspension for repeated policy violations, and in some cases, blocks on specific routes. For Zapier automations handling time-sensitive workflows — appointment reminders, lead follow-ups, verification codes — silent message filtering is a critical failure mode that is hard to diagnose without understanding the A2P compliance layer. The message sends without error in Zapier and in Twilio's API response, but the recipient never receives it.

For help designing a Zapier SMS automation that routes through the correct number type with proper compliance registration, or auditing an existing SMS workflow for delivery issues, talk to Automation Ace. For background on how webhook-triggered automation interacts with SMS delivery, see what is a webhook. If you're setting up a new messaging number, Twilio's signup is here.