Text-to-speech API phone call demo

Whether for AI agents, customer service, dynamic IVRs, or on-call assistance, a text-to-speech API lets you generate lifelike speech in real time and control the call flow from start to finish.

Choosing the right provider matters. Telnyx gives you access to a wide range of high-quality TTS voices including Telnyx, Google, Azure and Amazon Polly, with deeper mid-call programmability so you can switch voices, update scripts, or inject new speech dynamically—all at a significantly lower cost than many CPaaS providers.

If you need flexibility, low latency, and the freedom to update your voice interactions mid-call, Telnyx’s API is built for you.

👉 Watch the demo to see text-to-speech on a phone call and learn how to add real-time voice to your product.

What is in the demo?

In this video, we go from zero to real-time TTS on a phone call in minutes. You’ll also hear us compare Telnyx NaturalHD voices, Azure neural voices, and Amazon Polly voices side-by-side to show how each provider handles clarity, tone, and responsiveness in phone conversations. Here’s what we cover:

1. Setting up your account
2. Buying a number
3. Setting up your Telnyx Voice API application
4. Where to test your webhooks (spoiler: webhook.site)
5. Testing different voices on voice playground
6. Making a live phone call with API commands
7. Generating real-time audio with the Telnyx text-to-speech API
8. Switching between Telnyx NaturalHD, Azure, and Amazon Polly voices

To follow along, you just need:

• A Telnyx account

During setup, you’ll grab two things (we show exactly where to find them in the video):

• Your Application ID from your Voice API application
• Your API key from the Telnyx portal

We show each of these steps in the demo so you can pause, copy, and test as you go.

Developer resources

1. Get started
2. Dial a number with the Voice API
3. List available voices
4. Turn text-to-speech with API