The technology of speech recognition is increasingly being adopted (via a speech recognition API) for allowing computing systems to recognize and respond to human speech. This groundbreaking technology has the potential to change lives, businesses, and how we interact with computers. Amazon’s Alexa, Apple’s Siri, and Google Assistant are some examples of consumer products in the wild leveraging the power of speech recognition APIs. Tech companies are using speech recognition APIs not only to make it easier for humans to communicate with computers but also to enable devices and programs to do more in less time.
To allow developers to access their features and integrate them into work environments, most speech recognition applications have exposed their APIs (Application Programming Interfaces). Consequently, developers can expand their capabilities and build intelligent systems that can identify the spoken language.
What is Speech Recognition?
Speech Recognition (aka Automatic Speech Recognition, computer speech recognition, & speech-to-text) is a capability which enables a machine or computer program to convert spoken language into text. Modern speech recognition uses deep neural network algorithms and can understand more than hundred languages.
We reviewed several voice recognition APIs based on the following four main criteria:
- API features: We assessed the various outstanding features of the voice recognition APIs.
- Number of languages supported: We examined the number of languages that each of the APIs supports.
- Price: We looked at the price of incorporating each of the APIs into applications.
- Ease of use: We examined the ease of integrating each of the APIs for recognizing the human voice.
Eventually, we came up with the following list of the top 10 best speech recognition APIs.
- Google Speech API
- IBM Watson API
- SpeechAPI
- Speech to Text API
- Text-to-Speech API
- Rev.AI API
- ReadSpeaker API
- Speech2Topics API
- Siri API
- Wit API
Table of Contents
Top 10 Speech Recognition APIs
TL;DR: Here’s a table summarizing our findings.
| API | API Features | Number of supported Languages | Price | Ease of Use |
| Google Speech API | Convert audio to text, enable voice searches, build voice-controlled cases | 120 | 0-60 minutes free per month. Over 60 minutes priced at $0.006 / 15 seconds | Easy |
| IBM Watson API | Convert audio to text, build voice-controlled cases, customize the model | 7 | Free plan and paid plans from $0.002 to $0.01 per minute | Easy |
| SpeechAPI | Suppress noise backgrounds, classify speech segments | Limited | Free | Easy |
| Speech to Text API | Convert audio to text | 1 | Free plan and paid plans from $500 to $1500 per month | Easy |
| Text-to-Speech API | Convert text to speech | 26 | Free plan and paid plans from $5 to $300 per month | Easy |
| Rev.AI API | Convert speech to text, punctuation and capitalization, timestamp generation, livestreaming transcription | Limited | Free plan and pay-as-you-go pricing | Easy |
| ReadSpeaker API | Convert text to speech | 20 | Free plan and varying paid plans | Easy |
| Speech2Topics API | Extract topic metadata from audible media for analysis | Limited | Free plan and varying paid plans | Easy |
| Siri API | Build voice-controlled virtual assistant | Limited | Free plan and paid plans from $4.99 to $99.99 per month | Easy |
| Wit API | Provide natural language processing and voice interface capabilities | Limited | Free | Easy |
1. Google Speech API
The Google Speech API, which is officially called Cloud Speech-to-Text, is a powerful API that allows you to translate audio to text using Google’s machine learning technology.
API features: The Google Cloud Speech-to-Text API enables you to convert short-form or long-form audio into text with unmatched accuracy. With the API, you can enable voice searches (such as “What is the time now”), command use cases (such as “Stop playing music”), transcribe audio from call centers, and complete many more actions. It can process real-time spoken language or audio stored in a file.
Number of languages supported: The API recognizes 120 languages and variants from around the world. It can automatically detect the type of language in the audio (limited to four languages).
Price: The Google Speech API is priced monthly according to the extent of usage. Processing 0-60 minutes is free while over 60 minutes is priced at $0.006 for every 15 seconds.
Ease of use: Google has provided extensive documentation that is full of code samples on how to use the API. Furthermore, there is a vibrant community of developers who can assist you with any integration challenges.
Google’s suite of speech and text APIs is impressive. Google Translate API complements Google Speech API. Developers are building feature rich apps using the power of Google Speech and Google Translate APIs. You can learn more about Google Translate API by following our tutorial on the API. (Check other language translation APIs)
Is there a Google Voice API?
Google Voice is a telephone service. It provides call forwarding, voicemail services, voice & text messaging etc. As of November 2020, there is no Google Voice API.
2. IBM Watson API
The IBM Watson Speech to Text API empowers you to translate audio into written text so that you can include accurate voice recognition capabilities into your work environment.
API features: The API allows you to automatically convert audio in real-time, build voice-controlled applications, and customize the speech recognition model to suit your content and language preferences. You can also use the API for a wide range of use cases such as transcribing audio from a microphone, transcribing call center recordings, or analyzing audio recordings using keywords.
Number of languages supported: The IBM Watson API supports seven languages.
Price: The IBM Watson Speech to Text API has a free plan that allows you to transcribe 100 minutes per month. For more extensive usage, it has different pricing tiers, which start from $0.02 per minute (for up to 250,000 minutes) to $0.01 per minute (for more than one million minutes).
Ease of use: IBM provides an extensive range of resources, documentations, and SDKs to help you in getting started fast and easily. There is also an active community of developers who can assist you in making the most of the API.
3. SpeechAPI
The SpeechAPI is a simple API that lets you add noise suppression and speech classification capabilities in your application.
API features: The SpeechAPI comes with features for processing the speech of files. You can use the API to recognize noise from nearly any type of speech stream and remove it without affecting the voice. The API can automatically suppress noise from a variety of sources such as passing cars, sirens, crying children, or background noise in a cafeteria. Furthermore, the SpeechAPI enables you to perceive speech segments inside an audio file and classify them based on various characteristics such as sentiment, speaker language, sex, and age.
Number of languages supported: The API supports a limited number of languages.
Price: The API is offered for free.
Ease of use: There is a simple and easy to follow documentation that allows you to embed the API without many programming hassles.
4. Speech to Text API
The Speech to Text API is a simple API that allows you to convert audio to written text, just as the name suggests.
API features: The API is powered by machine learning technologies to assist you in transcribing speech accurately and fast. You can use it for converting both short-form and long-form audio.
Number of languages supported: The Speech to Text API supports only the English language. It automatically recognizes all accents (UK, US, and others), enabling you to perform conversions with minimal deviations.
Price: You can use the API for free, but you’ll be limited to 60 minutes per month. For more extensive usage, you can go for either the ULTRA plan (priced at $500 per month and limited to 15,000 minutes per month) or the MEGA plan (priced at $1500 per month and limited to 60,000 minutes per month).
Ease of use: The API is easy to use. There is simple documentation that enables you to quickly get started implementing it.
5. Text-to-Speech API
The Voice RSS Text-to-Speech API is a simple API that lets you convert textual content to speech, just as the names suggests.
API features: You can leverage the speech synthesis system that the API offers to convert normal language text into human speech. With just a few lines of code, you can connect to the API and enable your application to provide auditory information.
Number of languages supported: The Text-to-Speech API offers a diverse range of human-sounding voices and supports 26 languages.
Price: You can access the API for free, but you’ll be limited to 350 requests per day. To access more advanced features, you can go for any of its paid plans, which starts from $5 to $300 per month.
Ease of use: There is comprehensive documentation provided in different popular programming languages, enabling you to integrate the API quickly and easily on any platform.
6. Rev.AI API
The Rev.AI API allows developers to access a robust speech recognition system and build speech-to-text capabilities into their applications.
API features: With the Rev.AI API, you can quickly and accurately convert human voice to text transcriptions and do more with your audio and video content. The API comes with a wide range of amazing features, including support for punctuation and capitalization, timestamp generation, ability to recognize multiple speakers and attribute text to each, and ability to transcribe speech to text during livestreaming.
Number of languages supported: The API supports a few number of languages.
Price: There is a free file-duration-per-fifteen-seconds quota of 240 per month. Thereafter, it is charged at $0.000875 each.
Ease of use: All the API’s public methods and objects are well documented to enable developers to consume it easily and fast.
7. ReadSpeaker API
The ReadSpeaker speechCloud API is a web-based API that enables you to convert text to speech and enhance the versatility of your software and devices.
API features: The API lets you access quality male and female voices that are capable of reading audio files produced from written texts. It comes with several parameters for allowing you to have full control over the generated audio, such as customizing the language, adjusting the reading speed, and changing the audio format.
Number of languages supported: The ReadSpeaker API supports about 20 languages and variants from around the world.
Price: You can try the API for free with a trial account. For extended usage, you’ll need to contact the API creators for specific pricing.
Ease of use: There is simple documentation and sample codes in various programming languages that assist in easily implementing text to audio conversion capabilities.
8. Speech2Topics API
The Yactraq Speech2Topics API is an analytics service that utilizes machine learning technologies to allow you to gain enhanced visibility of your audible data.
API features: The API extracts topic metadata from any audible media, such as call center calls, written text, audio, or video content. Consequently, it delivers important insights you can use to make business intelligence decisions. For example, you can use the metadata to create targeted advertisements, create UX features that enhance user interaction, and mine relevant YouTube videos for meeting your brand sentiment needs.
Number of languages supported: The Speech2Topics API supports a limited number of languages.
Price: There is a free trial account for testing the capabilities of the API. Thereafter, you’ll need to contact Yactraq for specific pricing.
Ease of use: Yactraq provides API documentation and online customer support on how to start using the API to uncover the hidden potential of your audible data.
9. Siri API
Siri by Voice Actions is an intelligent virtual assistant that allows users to utilize natural language voice commands to complete various actions, just like Apple’s Siri service.
API features: The Siri API allows you to empower your application to respond to natural language questions. It offers an interface to the useful features that users need in any modern voice-controlled personal assistant. With the API, you can build applications that allow users to talk to their phones or computers and complete various actions such as voice dialing contacts, getting navigation information, and searching for images. Furthermore, it offers helpful metadata for carrying out sentence analysis as well as entity extraction.
Number of languages supported: The API supports a limited number of languages.
Price: You can access the Siri API for free, but you’ll be limited to 30 requests per day. To increase your limits, you can go for any of its paid plans, which starts from $4.99 per month to $99.99 per month.
Ease of use: Voice Actions has provided detailed documentation on how to integrate the API quickly and without many hurdles.
10. Wit API
The Wit API provides natural language processing and voice interface capabilities, which you can use to create applications and devices that can interpret users’ speech.
API features: With the Wit API, you can include state-of-the-art natural language interface to your application so that users can simply talk to express their intent, instead of following complicated steps or clicking many buttons. For example, you can use the API to create voice-controlled commands, robot dialog interfaces, and Siri-style personal assistant.
Number of languages supported: The API supports a limited number of languages.
Price: It is provided for free.
Ease of use: Wit provides comprehensive documentation, easy to follow tutorials, and code samples on how to use the API.
That’s Rakuten RapidAPI’s list of top 10 best speech recognition APIs. We hope you’ll find an API that you can use to convert human language into text, build voice-controlled applications, or complete other speech recognition tasks.
About Rakuten RapidAPI
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