# Twilio A2P

Welkin Health uses Twilio to power SMS messaging to patients. To comply with US carrier regulations, organizations that send text messages to patients must register their phone numbers and use case through the A2P 10DLC (Application-to-Person, 10-digit long code) program. This page explains what A2P 10DLC is and what your organization needs to do.

## What is A2P 10DLC?

A2P 10DLC is a system established by US mobile carriers (AT\&T, T-Mobile, Verizon, etc.) to regulate business text messaging. It distinguishes between peer-to-peer (personal) texts and application-to-person (business) texts. Since Welkin sends automated and templated SMS messages to patients, those messages fall under A2P rules.

**Why it matters:** Without A2P registration, messages may be filtered (blocked or sent to spam) by carriers, degrading message deliverability to patients.

## What Welkin handles vs. what you provide

**Welkin handles:**

* Twilio account provisioning for your organization
* Technical integration with Twilio
* Message sending and delivery via the Twilio API

**You (the organization) must provide:**

* Your organization's legal business name and EIN (Employer Identification Number)
* The business type and industry
* A description of the messages you'll be sending (the "use case")
* Sample message templates
* Opt-in and opt-out language confirmation

## Registration steps

Your Welkin implementation team will guide you through the registration process. At a high level:

### Step 1: Brand registration

Your organization is registered as a brand in the A2P ecosystem. This establishes your identity as a legitimate business sender. Required information:

* Legal business name (as registered with the IRS)
* EIN / Tax ID
* Business type (e.g., healthcare, non-profit)
* Business address and website
* Vertical/industry (Healthcare)
* Contact information for the registration

### Step 2: Campaign registration

A campaign defines how you use SMS – the message types you send. For a healthcare organization, your campaign description typically covers:

* Appointment reminders
* Care coordination messages
* Clinical check-ins and surveys
* Billing notifications (if applicable)

Sample messages are required – provide 2–3 example messages representative of what patients receive.

### Step 3: Opt-in and opt-out compliance

US carriers require that:

* Patients have opted in to receive messages from your organization (documented consent)
* Every message campaign supports an opt-out mechanism – patients can text **STOP** to unsubscribe
* Opt-out requests are honored within 24 hours

Welkin automatically handles STOP/HELP/START keyword responses and suppresses messages to opted-out patients.

## Timeline

A2P registration typically takes 2–4 weeks once all information is submitted. During this time, you can use Welkin in testing mode with sandbox phone numbers. Message deliverability may be limited until registration is complete.

## Ongoing compliance

* Do not send messages outside the registered use cases without updating your campaign registration
* Keep opt-in consent records for each patient who receives SMS
* Review message deliverability reports regularly – high opt-out or complaint rates can affect your sender score

Contact your Welkin CSM if you need to add new message types or change your phone numbers after initial registration.


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