What is a Voice API?

Mobile phone with coding and cloud icons

In a voice-driven world, talking via technology can be a click of a button to start a chat with your best buddy.

For businesses, the question that immediately comes to mind is “do your customers need to book an appointment, get customer support, or make a purchase?” Technologies that use voice APIs offer an easy-breezy way to do it without lifting a finger (except to tap their screens). And the payoff? A possible increase in revenue to the tune of 10-15% from voice calling APIs. That’s not just chump change. 

To achieve this CX, businesses can use voice calling APIs to reduce call handling time and increase customer satisfaction (among other intangible improvements to experience). The best part—you don’t need a telecom wiz to build complex telephony systems from scratch to reap these benefits.

Keep reading to discover how a voice API does the heavy lifting for customers and developers alike.

What is a voice API, and how does it work?

A voice API allows developers to integrate and automate inbound and outbound voice calling functionalities into applications, software, and networks.

Think of it this way: if your app wants to send a text message, it uses a messaging API to communicate with the phone network. A voice call API does the same thing but for voice conversations. How? That’s where Hypertext Transfer Protocol Secure (HTTPS) comes in.

Let’s say your application wants to make a phone call. It sends instructions via code to the voice API using an HTTPS-based interface. The voice-calling API then translates these instructions into commands carried out on the phone network (and back). This also means the developers only have to worry about the voice services they want to embed, leaving the telecom part of the equation to the voice API provider.

Here are some key voice call API features developers can add to applications:

  • Call control: By building custom call flows, you can easily transfer, bridge, or forward calls—and so much more. 
  • Text-to-speech and speech-to-text: Convert any message into audio in multiple languages and vice versa for audio transcription.
  • Media playback: Deliver a pre-recorded informational message or some jazzy hold music to keep your callers entertained.
  • Conferencing: Connect numerous people in a single call or allow a supervisor to listen in privately.
  • Recording: Capture voice calls in mono or dual-channel format to improve training, compliance, or customer experience. 
  • Real-time transcription: Convert speech to text to use as live captions, meeting notes, or activating keyword-based logic.
  • Answering machine detection:  Automatically detect when a person answers so you can play a message, route the call, or leave a voicemail.
  • Media streaming: Fork live calls to AI/ML solutions for sentiment analysis, voice biometrics, or two-way voice bots.

Let’s explore more use cases for voice calling APIs

Product developers are upleveling CX in new and innovative ways by embedding communications into their applications. With the voice channel, you could build:

1. Phone number masking for the gig economy
Your personal phone number is just that—personal. For apps like Uber and Rover, a voice call API helps avert a potential privacy nightmare for either clients or customers by providing temporary, anonymized numbers.

2. Call recording and transcription for human resources
Voice calling APIs can capture and convert phone interviews into text. With a written transcript, a hiring manager can do away with frantic note-taking, review conversations with the team, and make thorough hiring decisions.

3. IVR system for inbound call trees
Voice call API can give you “press 1 for support, press 2 for sales”—but it can also offer a significant upgrade. Callers can speak a command into the phone before being quickly routed over to the right department. Even better, other issues can be resolved without a human agent intervening by using advanced logic.

4. Voice alerts and notifications for updates at scale
In education, when news needs to spread to parents or students, a voice calling API gets your message out fast. Announcing a snow day? Reminding everybody about an upcoming event? With automated voice recordings, everyone from busy parents to forgetful students can stay in the loop.
For the healthcare industry, a voice call API ensures patients get important memos, such as appointment reminders or prescription notifications. That means fewer no-shows! These automated calls help keep the doctor’s office operating smoothly and patients on top of their health.

6. Conversational AI for customer service
Deliver a more personalized CX by feeding real-time call audio to advanced tools and AI algorithms. For example, when a frustrated customer calls in, the voice call API can engage a sentiment analysis tool to listen for their tone of voice and assist in turning a negative conversation into a positive one.

7. Click-to-call for easy connections
Create a super simple user experience within your application by embedding click-to-call. With the click of a button, a call is placed using the voice API before traversing over a SIP network for the highest call quality. Another way to power click-to-call is with WebRTC technology, which enables calls from or between applications.

So, how do programmable voice APIs stack up against legacy solutions?

Most technology leaders are already seeing big benefits from APIs. In one study from Google, 61% report that APIs help enhance digital experiences and products, while 54% believe they speed up innovation through collaboration.

As for a programmable voice API, the advantages far outweigh those of a SIP-based infrastructure if you’re a product developer:

Voice APISIP Telephony
Infrastructure requirementsIt’s all in the cloud! No big, clunky hardware is required. Requires complex setup and maintenance of on-premise equipment.
Ease of configurationDevelopers can create voice-enabled apps using HTML without telecom expertise.Demands telecom knowledge for proper implementation and management.
Flexibility factorTweaking a few lines of code is all it takes to make an update or implement another feature.It’s not as readily adaptable at a moment’s notice—and can be cumbersome or time-consuming to modify.
Cost-effectivenessPay-as-you-go pricing for usage that helps businesses scale up (or down) based on demand.The steep upfront investment, ongoing maintenance expenses for the hardware, and pay-as-you-go for usage.

Getting started with voice API

If you’re sold on the benefits of using a voice call API, next comes a critical decision: choose the right voice API provider. How do you find the best provider to help build your product? Here’s what to look for:

Is the voice calling API provider known to deliver high-quality connections? 
When it comes to voice interactions, crystal clear call quality and network reliability is non-negotiable. Seek out a company with a redundant network that guarantees minimal downtime, drops, or glitches—even during surges in call volume.

Are robust developer resources available? 
The right voice call API provider equips your developers with everything they need to create a customer voice experience. You should expect API guides, API technical references, SDKs for popular programming languages, and 24/7 expert support teams.

Do they offer extensive global coverage? 
You’ll need coverage for your current target market or regions you operate in. But you’ll also need room to grow so you’re covered no matter where you expand. Bandwidth’s Voice API offers expansive coverage that enables developers to build voice applications once and deploy them around the world.

Build with Bandwidth

Your next adventure with programmable voice communications doesn’t have to be a total system overhaul overnight. You can request a Voice API trial to explore your use cases’ ideal features and functionalities. Or chat with one of our API experts to discuss how you can effectively implement voice capabilities across your business.