Add high-quality voice conversations to applications with voice API

Easily add inbound and outbound voice calling API into your application with feature-rich call flows—no telecom infrastructure needed. All with one programmable voice API.

Give your customer’s voice new reach with Bandwidth’s Voice API

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

Easy as API

Voice-enabling your application is as easy as sending and receiving HTTPS requests. Developers can quickly can use any software language with our Voice API – including Node, Java, Ruby, Python, and C#.

Support at every step

Lean on our voice API experts and support teams to knock down any roadblocks for your dev team and take your voice capabilities to the next level. We hold ourselves accountable through SLA achievement, a near perfect CSAT benchmark and a focus on ensuring your success.

Global IP network

Our owned and operated network has a global reach of 65+ countries for the quality, control, and coverage to scale voice API efficiently.

Scale up (or down)

You’ll get custom voice API pricing only a network operator can provide for the throughput and capacity your applications need.

Scale across platforms, without sacrificing key voice API features

Create a customer voice experience with all the voice API features you need to control and modify your call flow in real time.

Call Control

Endless ways to customize a call flow with call transfers, bridging, forwarding, and more.

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Text-to-Speech (TTS)

Convert messages into audio in nearly 30 languages. Choose an Enhanced voice for a human-like sound.

Speech-to-Text (STT)

Convert audio into text for a call transcription. Choose Real-Time for live or instant access.


Record calls and voicemails in mono or dual-channel format, with 30 days of free storage.

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Connect up to 20 people at once, or enable call whisper for coaching.

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Answering Machine Detection

Connect to an agent if the call is answered, or leave a voicemail via audio file playback or TTS.

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Media Streaming

Fork real-time call audio via WebSocket to services like AI or machine learning.

Save money on every call with our Voice API

Since we own our tier-1 network, as well as the APIs, we can give you pricing that other voice API 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.

ServiceBandwidthTypical competitor
US local phone number$0.30 per month$1.15 per month
US local outbound$0.01 per min$0.014 per min
US local inbound$0.0055 per min$0.0085 per min
Standard Text-to-Speech$0.0007 per 100 char$0.0008 per 100 char
Enhanced Text-to-Speech$0.003 per 100 char$0.0032 per 100 char
Standard Transcription$0.045 per min$0.05 per min
Real-Time Transcription$0.047 per min$0.05 per min
Recording$0.002 per min$0.0025 per min
Conferencing$0.0015 per min$0.0018 per min
Answering Machine Detection$0.006 per call$0.0075 per call
Media Streaming$0.0035 per min$0.004 per min
Based on average competitor prices as of August 2023.

How does the Voice API work?

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

So rather than acquiring 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.

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 = "http://myapp.com/announce"

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


    return response.to_bxml()

An API 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.

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.

If you can think of it, our voice call API can do it

IVR System

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

Call Tracking

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


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

Voice Alerts & Notifications

Send automated voice recordings to your customer’s phone, providing reminders, notifications, and alerts.

Conversational AI

Build meaningful customer experiences by streaming real-time call audio to a voice bot, sentiment analysis, or voice biometrics tool.

Number Masking

Anonymize voice conversation by masking real phone numbers with proxy numbers, creating additional privacy for either calling party.

Call forwarding

Redirect incoming calls to an alternate phone number for ad tracking, time-of-day routing, or completing calls to text-only numbers.

Have another idea? Let’s talk.

Bandwidth’s Voice API in action: industry use cases

“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

Change how you and your customers make voice calls

Frequently asked Voice API questions