VOICE CALLING API

Add high-quality voice conversations to applications

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

Give your customers’ voice new reach

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, C#, and Python.

Support at every step

Lean on our 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 efficiently.

Scale up (or down)

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

Scale from zero to unicorn, without sacrificing features

Create a customer voice experience with all the 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.

Recording

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

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Conferencing

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

Since we own our tier-1 network, as well as 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. 

ServiceBandwidthTypical competitor
US local phone number$0.30 per month$1.15 per month
US local outbound$0.0100 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$0.0030 per 100 char$0.0032 per 100 char
Standard Transcription$0.0450 per min$0.0500 per min
Real-Time Transcription$0.0470 per min$0.05 per min
Recording$0.0020 per min$0.0025 per min
Conferencing$0.0015 per min$0.0018 per min
Answering Machine Detection$0.0060 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 a HTTPS-based interface without the hassle of handline 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]
    )

    response.add_verb(speak_sentence)
    response.add_verb(transfer)

    return response.to_bxml()

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. Create a phone tree that gets customers to the right person faster.

Call Tracking

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

Click-to-Call

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 customers’ 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.

“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