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

# Phone Number Guide

CallCow uses Twilio to handle phone calls. To connect your own Twilio account, you'll need to get a phone number and API credentials.

## Getting a Twilio Phone Number

1. Sign up for a Twilio account at [twilio.com](https://www.twilio.com)

2. Once logged in, go to **Phone Numbers** > **Manage** > **Buy a number**

3. Search for a number by country, area code, or capabilities (Voice, SMS)

4. Click **Buy** to purchase the number

5. Copy the phone number and add it to your CallCow workflow settings

## Getting Your Twilio API Credentials

1. Log in to the [Twilio Console](https://console.twilio.com)

2. On the dashboard, locate your **Account SID** and **Auth Token**

3. Click the eye icon to reveal your Auth Token

4. Copy both the Account SID and Auth Token

5. Paste these credentials into CallCow's Twilio integration settings

**Note:** Keep your Auth Token secret. Never share it publicly or commit it to version control.

## Setting Up SMS

To enable SMS capabilities for your Twilio phone number, you need to configure a TwiML App and connect it to your number.

1. In the [Twilio Console](https://console.twilio.com), go to **Messaging** > **Services** and click **Create Messaging Service**

2. Give your service a name and click **Create Messaging Service**

3. Under **Sender Pool**, click **Add Senders** and add your Twilio phone number

4. In the **Integration** step, select **Send a webhook** and enter your CallCow webhook URL as the **Request URL**

5. Complete the setup and click **Save**

6. Back in CallCow, enable SMS for your workflow and select the phone number you configured

**Note:** If you're on a Twilio trial account, you can only send SMS to verified phone numbers. Upgrade your account to send SMS to any number.

## Concurrent Calls Limit

CallCow uses Twilio for phone calls. By default, Twilio accounts have the following limits:

| Account Type                        | Calls Per Second (CPS) | Concurrent Calls |
| ----------------------------------- | ---------------------- | ---------------- |
| Trial                               | 1 CPS                  | 4                |
| Upgraded (without Business Profile) | 1 CPS                  | Limited          |
| Upgraded (with Business Profile)    | Configurable           | Unlimited        |

**Key points:**

* CPS limits only apply to outbound API calls, not inbound calls
* If you need higher throughput, you can increase your CPS limit in the [Twilio Console](https://console.twilio.com) Voice Settings page (requires an approved Business Profile)

For more details, see [Twilio's documentation on call limits](https://support.twilio.com/hc/en-us/articles/223180028-How-Fast-Can-I-Place-or-Receive-Phone-Calls-with-Twilio).