> ## Documentation Index
> Fetch the complete documentation index at: https://docs.autocampaign.ai/llms.txt
> Use this file to discover all available pages before exploring further.

# SMS channel

> Send and receive text messages through Twilio or Telnyx, with numbers, messaging services, and 10DLC.

## Overview

The SMS channel is Autocampaign AI's two-way texting feature. You connect one SMS
[provider](/getting-started/glossary#provider) — [Twilio](/providers/twilio) or
[Telnyx](/providers/telnyx) — and Autocampaign AI handles sending, incoming replies,
and delivery status. It also handles [A2P 10DLC](/compliance/a2p-10dlc)
registration (the US carrier registration required to send business texts from a
local number).

<Info>
  **Time to complete:** \~30 minutes to connect and add numbers, plus 1–2 days for
  10DLC carrier approval  ·  **Difficulty:** Intermediate
</Info>

<CardGroup cols={2}>
  <Card title="Connect Twilio" icon="plug" href="/providers/twilio">
    Uses your Account SID and Auth Token (two codes from your Twilio account).
  </Card>

  <Card title="Connect Telnyx" icon="plug" href="/providers/telnyx">
    Uses an API key (a password that lets Autocampaign AI use your Telnyx account) with Messaging scope.
  </Card>
</CardGroup>

## How the SMS channel is organized

<Steps>
  <Step title="Provider" icon="plug">
    Your connected Twilio or Telnyx account. Only one is active per workspace.
  </Step>

  <Step title="Messaging service / profile" icon="gear">
    A group for your phone numbers. It also holds the
    [webhook](/getting-started/glossary#webhook) (the automatic link that delivers
    replies to Autocampaign AI) and your 10DLC campaign link. Twilio calls it a
    **messaging service**; Telnyx calls it a **messaging profile**.
  </Step>

  <Step title="Phone numbers" icon="hashtag">
    The numbers you send from, attached to a messaging service.
  </Step>

  <Step title="10DLC brand & campaign" icon="shield-check">
    Carrier registration that lets you send to US numbers reliably.
  </Step>
</Steps>

## Set up the SMS channel

1. **Connect a provider** — see [Twilio](/providers/twilio) or [Telnyx](/providers/telnyx).
2. **Register your brand** — [A2P 10DLC](/compliance/a2p-10dlc).
3. **Create a messaging service / profile** and attach phone numbers.
4. **Register a campaign** and start sending.

The **Set Up Your Channel** wizard guides you through these in order right after
you connect.

## Buy and assign numbers

On the SMS channel's **Numbers** tab you can:

* **Buy a number** — filter by country, area code, or digits the number should
  contain. Choose what it can do (SMS for texts, MMS for pictures, Voice for
  calls), and purchase.
* **Assign a number** to a messaging service using the dropdown in its row.
* **Create a messaging service** with a friendly name.

## Voice calls on your SMS numbers

[Calls](/inbox/calls) run on the same provider as your SMS channel. A number can
place and receive calls only if it has the **Voice** capability at your provider.
If you switch messaging provider, turn voice back on under **Settings → Voice**.

## Replies, delivery, and opt-outs

* **Replies** arrive in your [Inbox](/inbox/overview), linked to the contact.
* **Delivery status** updates automatically. Your provider reports it through
  webhooks, which are set up for you.
* **Opt-outs** (STOP) and **opt-ins** (START) are detected on every incoming message
  — see [Opt-out](/compliance/opt-out) and [Opt-in](/compliance/opt-in).

## FAQ

<AccordionGroup>
  <Accordion title="Which provider should I choose?">
    Both are reliable, large carriers. Choose based on your existing account,
    pricing, and number availability. Twilio uses an Account SID and Auth Token;
    Telnyx uses an API Key with Messaging scope.
  </Accordion>

  <Accordion title="Can I send MMS?">
    Yes, if your number and provider support it — turn on the **MMS** capability
    when buying a number.
  </Accordion>

  <Accordion title="Do I set up webhooks myself?">
    No. Autocampaign AI sets up the webhooks for replies and delivery status on your
    messaging service automatically when you finish setup.
  </Accordion>
</AccordionGroup>

## Troubleshooting

<AccordionGroup>
  <Accordion title="Why do my messages fail to send?">
    Confirm the channel badge is **Active**, the sending number is attached to a
    messaging service, and — for US traffic — your 10DLC campaign is approved.
  </Accordion>

  <Accordion title="Why aren't replies showing in the inbox?">
    Finish the setup wizard so the webhooks are set up, and confirm the number
    belongs to a messaging service that Autocampaign AI manages.
  </Accordion>
</AccordionGroup>

<Card title="Register for 10DLC" icon="shield-check" href="/compliance/a2p-10dlc">
  Required for reliable US SMS delivery.
</Card>