Application Programming Interfaces – more commonly known as APIs – are a method of connecting computers and/or computer programs together to provide a service to an end user. One of the most functional APIs is what’s known as ‘Audio to Text’, ‘Voice to Text’ or speech recognition APIs. Audio to Text APIs are characterized by their ability to improve their understanding of a user’s voice over time through the use of advanced AI algorithms and huge databases of 100+ languages. Let’s explore the best options!
How Do Voice to Text APIs Work?
It’s important to note that the users themselves don’t generally interact with the API directly. It’s a back-end function. Speech recognition applications are different from speech recognition APIs. Applications (Cortana, Alexa etc.) are what the end user sees and hears. APIs are the engine behind it.
Audio to text may seem like a straightforward process to the end user, but there’s quite a lot going on in the background to produce an instant, accurate version of what’s being said.
Let’s break it down step-by-step:
- The user talks into a microphone, which sends the audio to the application.
- The application breaks up audio into small snippets of data called ‘phonemes’ – distinctly different units of sound, unique to each language (the English language has 44 of them).
- The software makes in informed decision of what the user is saying, based on how the phonemes are organized.
- The API then consults a language database to make an informed decision on what the user was likely to have said.
- The software transmits displays the written text within an application.
The Top 5 Voice to Text APIs
Speech recognition software is highly popular and universally easy to use. Given that the technology is at the forefront of modern neural networking and AI research, products and methodologies are in a constant state of development.
Now that you understand how the software works, let’s look at the best Voice-to-Text APIs available (in no particular order). Read on to help you decide on what API is best for your organization or application.
1. IBM Watson STT API
IBM Watson STT is a well-supported, highly customizable API that draws on IBM’s experience as a leading provider of enterprise IT services. Its selling point is the number of resources that are made available to you once you start using it, from software development kits to best practice documentation.
When it comes to pricing, IBM Watson STT offers up to 100 minutes per month without charge. After that, the fees begin.
Number of languages supported: 7
- Built-in API development
- Commercial transcription (call centres and SEO functionality)
- Vast knowledge base
- Limited language support
2. Rev.AI
An increasingly popular speech-to-text platform that’s modelled on 50,000+ hours of transcribed speech and driven by DevOps/Agile KPIs such as ‘time to market’ and scalable CI/CD.
When it comes to pricing, Rev.AI charges per minute in a pay-as-you-go tier and an enterprise tier.
Number of languages supported: 31
- Multiple speaker recognition
- Support for asynchronous and streamed audio
- Cataloguing functionality for searchable transcript repositories
- Can be slower than average over short form transcriptions
3. Google Speech API
Google’s very own speech API remains one of the most popular audio to text platforms in the world, and benefits from some of the best minds in the field of AI research to develop its voice recognition features. Find Google Speech’s pricing tiers here.
Number of languages supported: 120
- Data logging options available
- Google Workspace functionality
- Automatic language detection
- Total monthly capacity is limited to 1 million minutes
4. Azure AI Services
Building on their status as a leading global provider of B2B/B2C tech services, Azure AI Services (formerly known as Microsoft Cognitive Services) offers enterprise-level speech recognition within its Azure framework. While there is a lack of specialized functionality, Microsoft have pledged to continue developing their machine learning division to broaden its operational scope in the coming years. Explore its pricing plans here.
Number of languages supported: 103
- Industry-leading security via the Microsoft Trust agreement
- Full integration with existing Microsoft IaaS/PaaS products
- Highly active development community
- Large volume specialized work can be pricey
- Lack of specialized API tools
5. Speechmatics API
Speechmatics is a cloud-based API that relies on intuitive front-end functionality and ultra-fast transcription speeds for high volume workloads. It is an enterprise-level application, so you’ll need to contact them directly for demonstrations and pricing. Explore their volume-based pricing here.
Number of languages supported: 31
- One of the best transcription engines available
- Broad range of integration features
- Lack of a free option
- Limited language support