6 Best Speech-to-Text APIs for Modern Applications in 2023

Speech recognition technology has advanced rapidly in recent years, leading to a boom in speech-to-text applications. This guide will summarize the speech tech landscape today and provide an expert overview of the top speech-to-text APIs available.

The State of Speech Recognition Technology

Speech recognition innovation has accelerated, with speech-to-text accuracy improving exponentially thanks to better algorithms, more training data, and enhanced computation capabilities.

To illustrate – back in 1995 word error rates averaged over 30%, while today top solutions score 95% accuracy and some now surpass human transcription precision.

Behind these striking accuracy gains is the application of techniques like convolutional neural networks, recurrent neural networks, gradients, and model ensembles by today‘s top speech technology companies.

Adding to the performance improvements, the quantity of training data for speech recognition models has grown tremendously. Models that once had just a few hours of sample audio now leverage thousands of hours of quality dataset.

Finally, leveraging scalable cloud infrastructure with its vast compute capacity has enabled processing far larger datasets to create extremely sophisticated models.

Together these advancements have elevated speech recognition utility, reliablity, and commercial adoption.The technology is now integrated widely – from clinical documentation software to customer support call analytics solutions to automobile infotainment systems.

And speech-to-text will become only more ubiquitous as developers further democratize its access. Programmable cloud APIs have reduced friction to integrate the capability, fueling use cases like dictation apps, smart speaker skills, and auto-generated media subtitles.

In fact, according to ResearchAndMarkets, the global speech recognition software market is expected to grow at an impressive 16% CAGR from 2022-2027 – reaching $28.3 billion in value on rising demand.

With speech tech proliferation in mind, this guide covers leading developer-friendly speech-to-text APIs capable of powering robust applications.

Benefits of Speech-to-Text APIs

Before reviewing top speech recognition APIs, let‘s discuss why converting speech to text programmatically is valuable:

1. Efficiency at Scale

Manual transcription is time-intensive, but speech-to-text automation enables scaling communications insights quickly across call centers, legal firms, healthcare systems.

2. Convenience Factors

Whether alleviating typing fatigue or assisting disabled users – speech UI heightens convenience.

3. Insights From Voice Data

Structuring spoken communications as text data unlocks opportunities for search, analysis, and archival. Imagine mining your company‘s 20 years of earnings call transcripts!

4. Wider Accessibility

Automatic speech-to-text expands information accessibility, powering closed captioning, voice commands, and more.

Now that the main advantages are covered, let‘s explore key use cases where speech APIs excel before listing top solutions.

Speech-to-Text Use Cases

Some leading ways businesses tap speech recognition include:

Media Transcription

Automatically generate text transcripts and subtitles from video and audio streams using speech-to-text. For example, news media editors can accelerate closed captioning and searchable metadata creation leveraging the technology.

Call Center Analytics

By transcribing customer service calls, quality assurance managers can surface key themes around pain points, agent behaviors, churn drivers, and more to enhance operations.

Legal Workflows

Law firms use speech recognition when processing client interviews, testimonies, and large caches of audio records to identify important details faster.

Voice-Enabled Apps

Speech-to-text powers voice assistant chatbots, smart speakers, screen readers for the blind, dictate-style document creation software, and other conversational applications.

Those use cases just scratch the surface of this adaptable technology‘s potential!

Top 6 Speech to Text APIs for Developers

Now let‘s get to the core content – expert insights on the leading cloud speech recognition APIs available today:

1. Amberscript

Amberscript specializes in highly accurate automated media transcription leveraging customizable speech models. Trusted widely across broadcasting and entertainment for subtitles and metadata generation, Amberscript integrates seamlessly into your workflows.

It enables you to:

  • Upload media files and receive readable, timecoded transcripts automatically formatted.
  • Extract searchable metadata like keywords and speaker changes from video.
  • Customize speech models to maximize precision for your audio conditions and vocabulary through training.
  • Adapt to speakers’ accents and audio environments like courtroom noise.
  • Support global audiences by detecting 80+ languages.

Accuracy: With specialized models, accuracy for noisy or accented speech reaches up to 90%

Supported Languages: 80+ including German, Chinese, Spanish, and more

Formats: mp3, mp4, mov, PDF exports

Pricing: Starts at $10 per hour of media processed after trial

Backed by strong R&D around speech data, Amberscript empowers creating accurate subtitles and enriched media analytics. Its customization tools help optimize for unique use case needs as well.

2. Rev.com

Rev serves leading call centers, market research firms, educational institutions, and more by providing a mighty speech recognition API.

It enables:

  • Real-time transcription to captions conferences, earnings calls, and events efficiently with limited lag.
  • Audio intelligence around detected topics, trends, keywords/phrases within recordings via summary reports.
  • Custom models tailored to your speakers and vocabulary for maximizing precision.
  • Support for 15+ languages like English, Spanish, German, and Arabic dialects.

Accuracy: Very high precision consistently, with ability to customize models further

Supported Languages: 15+ languages supported

Formats: mp3, mp4, wav, streaming audio

Pricing: Starts at $0.008 per minute, discounts for annual commitments

With Rev you get powerful speech analytics capabilities on top of accurate base transcriptions – making it easy to extract actionable insights.

3. Google Cloud Speech-to-Text

Google Cloud offers its speech recognition prowess through Cloud Speech-to-Text. Tap Google‘s models trained on thousands of hours of speech data across over 125 languages – or train custom models optimized for your audio.

Benefits include:

  • Audio transcribed into text quickly and accurately.
  • Detects speaker changes and explicit content within recordings.
  • Real-time conversions supported for captioning use cases.
  • Cost efficiency leveraging scalable Google Cloud infrastructure.

Accuracy: Very precise transcription leveraging robust models

Supported Languages: 125+ global language options

Formats: flac, mp3, m4a, wav and more

Pricing: 60 minutes free per month, then $0.006 every 15 seconds

If you need to ingest lots of audio data for searchability or analysis, this API delivers Google-grade performance adapted to your data at enterprise scale.

4. AssemblyAI

AssemblyAI takes an innovative approach – applying bleeding-edge deep learning research to speech recognition challenges today.

It powers diverse features like:

  • Speaker separation – isolating distinct speakers from single channel recordings.
  • Multi-topic modeling – discovering underlying topics by analyzing patterns.
  • Sentiment analysis – detecting emotion present within recordings.
  • Content filtering – automatically masking profanity and sensitive data.

Accuracy: Very precise, leveraging latest ML advancements

Supported Languages: English, with additional languages coming

Formats: common audio formats

Pricing: Pay per second transcoded starting at $0.0025, free trial

For those leveraging speech analytics, AssemblyAI provides handy enrichments to create text transcripts packed with actionable insights.

5. IBM Watson Speech to Text

Veteran technology company IBM Cloud offers its battle-tested Watson Speech to Text API for speech recognition.

It empowers:

  • Transcribing customer calls with detailed conversational analytics – detecting keywords, sentiment, speakers, follow-up actions and more.
  • Creating voice-enabled virtual assistants that understand natural commands using machine learning.
  • captioning media files at scale.

Accuracy: Very precise transcription leveraging robust models

Supported Languages: 10+ languages supported like English, Korean, Japanese

Formats: .wav, .mp3, and more industry standard codecs

Pricing: Pay only for what you use, starting at $0.02 per minute – discounted for annual plans

IBM offers mature speech technology you can trust with Watson‘s enterprise-grade speech to text API – complete with robust analytics features.

6. Scriptix

Scriptix delivers automated speech recognition capabilities presented in an approachable way for developers.

It provides:

  • Accurate speech-to-text including punctuation and formatting.
  • Tools to redact sensitive entities detected like names, places etc.
  • Multilingual transcriptions across 9 languages currently.
  • customizable vocabulary per industry for greater relevance.
  • Separates speakers from single channel recordings.

Accuracy: Very competitive accuracy while providing advanced controls

Supported Languages: Danish, Dutch, English, French and 5+ more

Formats: mp3, mp4, common formats

Pricing: Subscription packages starting at $99 monthly for 180 minutes of speech

Scriptix makes it easy to integrate top-tier speech recognition into apps via API – complete with handy formatting, redaction, and analytical tools.

Speech-to-Text APIs Comparison

API Accuracy Languages Formats Pricing Common Uses
Amberscript Custom models for optimal precision 80+ languages Media files $10 per hour Transcription, subtitles
Rev Very accurate, adaptable 15+ languages Audio files, streams Starts at $0.008 per minute Call analytics, conferences
Google Speech-to-Text Top-tier precision 125+ languages Audio files, streams $0.006 per 15 sec Heavy-use media apps
AssemblyAI Cutting-edge accuracy English (more coming) Audio formats $0.0025 per sec Analytics-rich use cases
IBM Watson Enterprise-grade accuracy 10+ languages Audio files Starts at $0.02 per minute Call analytics, assistants
Scriptix Very accurate, formatting controls 9 languages Common formats Starts at $99 monthly General transcription

As shown in the comparison, these speech recognition APIs service a breadth of use cases with minor differences in tools and pricing to suit needs.


Advanced speech-to-text technology is transforming interactions – fueling everything from health record dictations to browser-based search. Speech recognition cloud APIs covered in this guide reduce barriers for developers seeking to integrate such capabilities today.

Hopefully this overview of the speech API landscape supplies valuable insights around options, technical features, ideal use cases and pricing models to inform your evaluation.

With quality speech transcription accuracy exceeding 97% in some cases now, the technology growth runaway seems poised to continue unfolding – making these developer tools only more relevant.

By leveraging speech cloud APIs, any platform can unlock conversational interfaces and turn previously siloed voice content into structured data capital.