Conversational AI • Last Updated 7/29/2024

What is Programmable Voice?

Learn everything you need to know about programmable voice - from most common use-cases, to how to choose a programmable voice API

By Pete Christianson

Man Programs on Multiple Screens

Programmable voice refers to the ability to make, receive and control phone calls using a voice API. A voice API not only enables your application to connect to your carrier network, it also enables your app to control your carrier service and perform various voice operations, like audio conferencing and call recording.

A voice API enables you to connect and control your carrier service with just a few lines of code. It’s essentially a developer’s shortcut to programmatically controlling your carrier network, without having to interface directly with the Public Switched Telephone Network (PSTN).

What can you build with programmable voice?

Developers typically use programmable voice APIs to build workforce applications with embedded communication or collaboration requirements. Some prime examples of fast growing use-cases include:

Contact center software

The best contact center software routes calls to the right agents, provides agents with the context they need, and supports an omnichannel strategy. Building your contact center application on a programmable voice API will result in a scalable, flexible solution—so you can add agents, locations, capabilities and numbers with ease.

Unified communications as a service

Gartner defines UCaaS as a cloud-delivered unified communications model that supports enterprise telephony, meetings, unified and instant messaging, mobility and communications-enabled business processes. These solutions are generally ready to go out-of-the-box and can be easily integrated with other business applications for additional benefits.

Businesses can now leverage UCaaS to centralize their internal communications between employees and their external facing dialogues with customers, all within a single platform. And, the benefits are significant - cloud solutions offer scalability and reliability at lower costs. Businesses also gain the ability to support omnichannel communications, resulting in productivity improvements.

Call tracking

The proliferation of smartphones and communications technology has made the digital marketing landscape more complex than ever. There are more ways than ever for brands to reach customers, and almost just as many ways for customers to contact businesses and make purchases.

So, that means it’s absolutely critical for call tracking applications to provide analytics and real-time intelligence. Call Tracking applications not only determine how callers found your business, they arm sales and marketing teams with data to help them measure the success of their marketing campaigns and optimize future marketing strategy.

Conversational AI apps

Both conversational AI and chatbots are software programs that use machine learning and natural language processing to communicate with humans and accomplish certain tasks. Typically, conversational AI refers to an artificial intelligence program that people interact with by speaking. Conversational AI is most often used for communicating with customers over the phone, where the AI responds to voice inputs.

Conversational AI and chatbots can enhance the communication channels that customers use most. And, customers have some expectations that companies will use automation to make certain buying and customer support activities easier and more convenient. Some examples include appointment scheduling and reminders in healthcare, and reservation or booking changes in hospitality.

How to choose a programmable voice API

Voice APIs are both highly configurable and easily consumable. Using APIs, companies of all sizes can embed secure and reliable omnichannel communications capabilities into their applications, to better meet the needs of today’s businesses, customers and end-users.

That’s probably why according to Cloud Elements 2019 State of API Integration Report, 55% of businesses say API integration is critical to their business strategy and why IDC predicts that 30% of enterprises will have communications embedded through an API by the end of this year.

However, only 35% of API developers say their organization’s API documentation is above average, with 35% of developers saying their organization's API documentation is poor or below average.

Voice API connectivity is important. But, as you can see from the numbers (and as you probably already know), you can’t use just any API. Some API developers make subpar APIs or support their APIs with inferior or incomplete developer documentation.

Your voice API provides a critical function for your applications. So, it pays to take the time to find an API with solid developer support, a powerful network, and the integrations you need to create the exact experience you want.

How much does programmable voice cost?

Costs for voice APIs vary depending on which provider you choose, call types, volumes and features you need. In general, providers overlay a standard cost for programmatic voice.

Here’s a quick comparison of Telnyx pricing vs. Twilio pricing to give you an idea:


Make Calls(Per Min)Receive Calls(Per Min)
Call typeTelnyxTwilio
TelnyxTwilio
Local calls$0.0070$0.0130$0.0055$0.0085
Toll-free calls$0.0020$0.0130$0.0170$0.0220
SIP, browser or app calls$0.0020$0.0040$0.0020$0.0040

Telnyx programmable voice FAQs

Here are the answers to some of our most frequently asked programmable voice questions.

How do I build with the Telnyx programmable voice API?

To get started, just sign up for a Mission Control portal account, then follow the four remaining steps in this quickstart guide to create a Call Control application, buy a number, assign it to your app and create an outbound voice profile. Then, you’ll be ready to start embedding voice into your application with one of our suite of SDKs.

Does Telnyx have text-to-speech capabilities?

Absolutely—we leverage Amazon Polly to provide a conversational experience, available across multiple languages and accents. Text-to-speech allows you to convert text to speech and play it back on the call. You can find out how to use the speak_text command in our developer center, along with handy code snippets.

Can I record calls with Telnyx programmable voice?

Yes, you can use the Telnyx voice API to record calls using the record_start command. You’ll find code snippets to help you do this quickly and easily in our developer center.

How much does Telnyx programmable voice cost?

You can find the latest pricing for Call Control [here]. Telnyx also offers even greater discounts as you scale, or when you’re ready to commit to monthly usage—talk to our sales team about your specific needs.

How does Telnyx programmable voice work?

The Telnyx programmable voice API (Call Control) framework is essentially a set of REST APIs that allow a developer to control call flows, from the moment a call is made or received to the moment the call is terminated. In between, you’ll receive a number of webhooks for each step of the call, which you answer with a command.

It's this communication back and forth of webhooks and commands that gives you granular control over your calls.

Can I use XML code with the Telnyx programmable voice API?

You can! We’ve developed a tool called TeXML Translator to make it super easy for you to use your XML based applications with the Telnyx voice API. Head over to our developer center to follow the TeXML setup guide to see just how easy it is to switch an existing XML application over to, or build a new one on, the Telnyx programmable voice API.

Questions about Telnyx programmable voice? Join our developer slack channel to have them answered 24/7 or sign up for the Mission Control Portal now to start building.

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