Skip to main content
Voice API

Voice API

Bandwidth’s programmable Voice API allows you to build a custom voice calling solution that’s right for you and your customers. Embed inbound and outbound calling capabilities directly into your application or product—all without the need for a telecom infrastructure of your own.

Talk to an expert


Give your customers’ voice new reach

Integrate and automate your voice calling needs with Bandwidth’s powerful and programmable Voice API

Easy as API icon

Easy as API

Made by developers for developers, our Voice API supports whatever language you’ve built your software on. This includes, PHP, Node.js, Ruby, C#, Java and Python, allowing easy embedded communications without having to start from scratch.

Our Developer Docs

Support at every step icon

Support at every step

Need help taking your voice capabilities to the next level or solving a sticking point for your devs? Many claim to be support-centric, but we prove it by just being easier to do business with. We hold ourselves accountable through SLA achievement, a near perfect CSAT benchmark and a focus on making sure you’re successful.

Our Support

Access our global IP network icon

Access our global IP network

We own and operate a global network, reaching 65+ countries and 90% of the global economy. This gives your business the quality, control, and coverage to scale efficiently around the globe.

Our Network

Simplified pricing & billing icon

Simplified pricing & billing

Because Bandwidth Voice APIs are backed by our very own network, you get access to pricing only a network operator can provide. Get custom pricing tailored to your needs when you have a custom or high volume use case.

Our Pricing

Scale from zero to unicorn, without sacrificing features

We know your solution requires a full-featured voice API, which is why you get access to all the tools you need with Bandwidth.

Bandwidth Voice API pricing

Based on average competitor prices as of October 2021.

Save money on every call

Since we own our voice network and the APIs, we can give you pricing that other providers can’t. And with 6-second billing increments, you only pay for the time you use, saving you and your customers money on every call.

How does the Voice API work?

A Voice API allows applications to access Bandwidth’s voice services using a HTTPS-based interface without the hassle of handling SIP infrastructure.

How does the Voice API work? diagram

How does the Voice API work? diagram

So rather than requiring a telecom expert, our Voice API allows you to access voice capabilities via a set of well-defined APIs that any web developer can use to rapidly develop communications enabled applications.


Want to know more?


Download Voice API Factsheet

Built for developers

Made by developers, for developers. Our powerful Voice API is dev friendly and has all the documentation you need to help you get voice up and running, no matter what you’re building.

View DocsSample Apps

We support a wide range of SDK’s.View SDKs

def transfer_call(): 

    """Transfer an incoming call to '+11234567892' with '+11234567891' as the Caller ID"""

    response = Response()
    speak_sentence = SpeakSentence(
        sentence = "Transferring your call, please wait.",
        voice = "paul"

    phone_number = PhoneNumber(
        number = "+11234567892",
        transfer_answer_url = ""

    transfer = Transfer(
        transfer_caller_id = "+11234567891",
        phone_numbers = [phone_number]


    return response.to_bxml()

Request your Voice API trial today!

Start the process to make calls with our Voice API, or talk to one of our experts to get your questions answered.

Request Trial Talk to an expert

Voice API support employee

If you can think of it, we have a use case for you

Our customers are always thinking of new and innovative ways to use our Voice API. Here are just a few of the things you can build. Have an idea we haven't thought of? Let's talk

IVR System Icon

IVR System

Build a better customer experience. Create a phone tree that gets customers to the right person faster.

Call Tracking Icon

Call Tracking

Accurately attribute calls using Bandwidth to build a carrier-grade call tracking & analytics platform.

Click to call Icon


Turn search traffic into business. Enable click-to-call to remove barriers for customers connecting with businesses.

Call Tracking Icon

Outbound Notifications

Send automated voice recordings to your customers' phone, providing reminders, notifications, and alerts.

Blue heart

“Delivering the highest quality, enterprise-grade phone service on the market is our top priority. Bandwidth’s network, plus their hands-on support, help us guarantee that our customers’ calls go through, everytime.”

Erol Toker, CEO & Founder, Truly

Truly logo

Network operators and CPaaS providers

The Bandwidth Difference

At Bandwidth, we combine the power of a carrier with the flexibility of an API platform to create a modern communications platform. Our APIs provide the reliability, scalability, and return on investment that our customers deserve, allowing them to create custom solutions that scale to their needs.

Change the way your customers make voice calls

Talk to an expert

Frequently asked questions

What is a voice API?

A voice API, or application programming interface, is a software connection that enables companies to embed the ability to make and receive voice calls into their applications, software, and networks.

What is 6-second billing?

While there are many ways to bill for voice services, Bandwidth uses 6-second billing. Unlike the standard 1-minute billing, this means you only pay for the time you use in 6-second increments, as opposed to 1 minute increments.

How many rate centers does Bandwidth support?

Bandwidth supports over 9,600 on-net rate centers, covering 93% of the U.S. population.

Do I have to use a Bandwidth number with the Bandwidth Voice API?

No. Bandwidth allows you to use numbers from other providers. That being said, Bandwidth has an industry-leading porting and number management experience, so you’ll want to have your numbers with us.

Does Bandwidth's Voice API have a UI or Voice XML?

Bandwidth’s Voice API has a Voice XML called BXML. You can learn more about it on our Developer Resource site. Bandwidth does not provide a UI for building call flows, etc.

Can I use Bandwidth's Voice API to enable calling in my application?

Yes. With the Bandwidth Voice API you can enable calling in your application. This includes toll-free voice, as well as inbound and outbound (or termination and origination if you prefer the telecom terminology) voice calling from your application or software.

Does Bandwidth's Voice API support international calling?

We support outbound calling to international numbers, provided your account has an international product provisioned. We don’t currently support calling from international numbers.

What use cases do you support with your Voice API?

There are a number of applications you can build with Bandwidth’s Voice API, including an IVR, click-to-call capabilities, call tracking, and conversational AI  to name a few. To see what else you can build with our Voice API, check out our use case page.

What kind of infrastructure do I need in order to connect to Bandwidth’s Voice API?

All you need is a server for your application that can connect to Bandwidth’s server. There’s no need to have a SIP switch to connect; we handle all the telecom so you can focus on building great applications.

What other APIs do you offer? Can I build with more than one of your APIs?

Bandwidth has messaging and emergency calling APIs, allowing you to build applications that can send and receive text messages, as well as contact emergency services.

What’s the difference between a call made via Voice API versus WebRTC?

While phone calls made using a Voice API can be powered over the internet (via DSL/cable modems), Wifi, and mobile networks, they also rely on a VoIP network to be completed. WebRTC calls are solely focused on browser-based communications, which can also be connected into phone calls via a provider like Bandwidth. Learn more about Bandwidth’s WebRTC solution.