# Telephony

The **Telephony SDK** allows you to offer your users all the features associated with a mobile phone number while preserving their privacy. The Sudo Platform makes it effortless to integrate phone numbers, messaging, and calling within your existing or new products. This enables your users to use different phone numbers for different situations, contexts or roles. In turn, this compartmentalization of their personal information helps keep them safe online.

Mobile phones have become so ubiquitous that a phone number is now synonymous with a user's identity. More and more services and applications require a user to share their phone number alongside their other personal data. This coupling of a phone number with personal identity carries significant privacy and security implications. If these are left unchecked, they expose users to significant threats such as identity theft, social engineering, SIM swapping, account takeovers, doxing, and more.

## Key Features

|                                                                  |                                                                                                                                                                         |
| ---------------------------------------------------------------- | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| [Phone Numbers](/guides/telephony/phone-numbers.md)              | Give your users their own phone numbers that work just like mobile number but with the privacy and security benefits of a Sudo.                                         |
| [SMS Messages](/guides/telephony/text-messaging.md#sms-messages) | Quickly and easily add secure SMS messaging to any app, giving your users the ability to send messages to or receive messages from any phone number.                    |
| [MMS Messages](/guides/telephony/text-messaging.md#mms-messages) | Allow your users to send multimedia messages such as photos, GIFs, videos, contact cards and more.                                                                      |
| [Voice Calling](/guides/telephony/calling.md)                    | Provide your users with the ability to make and receive voice calls to mobile, toll-free, landline, and VOIP phone numbers without revealing their device's SIM number. |

## Next Steps

* Integrate the **Telephony SDK** into your [iOS](/guides/telephony/integrate-the-telephony-sdk.md#integrate-the-ios-sdk) and [Android](/guides/telephony/integrate-the-telephony-sdk.md#integrate-the-android-sdk) applications
* Learn more about [Sudo digital identities](/concepts/sudo-digital-identities.md) and other core concepts


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