Streamline Your Projects with Real-Time Transcription: A Comprehensive Guide to AssemblyAI's Streaming Speech-to-Text API

Streamline Your Projects with Real-Time Transcription: A Comprehensive Guide to AssemblyAI's Streaming Speech-to-Text API


In today's fast-paced digital world, the ability to transcribe audio content accurately and swiftly has become indispensable for professionals across various industries. From journalists and content creators to researchers and educators, the demand for efficient transcription services is on the rise. Recognizing this need, AssemblyAI presents its cutting-edge Streaming Speech-to-Text (STT) solution, designed to transform live audio streams into precise text transcriptions with minimal latency. This guide aims to introduce you to the remarkable capabilities of AssemblyAI's STT technology, ensuring you get started on leveraging its potential to streamline your workflows and enhance productivity.

The Essence of Streaming Speech-to-Text

AssemblyAI's Streaming STT service stands out by offering real-time transcription capabilities. Unlike traditional transcription services that require audio files to be fully recorded before transcription can commence, our Streaming STT allows you to transcribe audio content as it's being captured. This real-time processing ensures that you can receive transcribed text within a few hundred milliseconds, facilitating immediate analysis and utilization of the content.

Supported Languages

At its core, the Streaming STT service by AssemblyAI is currently tailored to comprehend and transcribe content in English. This focus on a single language enables us to refine our algorithms and deliver transcriptions with a high degree of accuracy. For users seeking transcription services in other languages, we encourage staying tuned as we continuously work on expanding our language offerings.

Getting Started with AssemblyAI

Embarking on your transcription journey with AssemblyAI is a straightforward process. We provide an array of official SDKs, including Python, JavaScript/TypeScript, Go, and Java, to accommodate your programming preferences. For those whose preferred language isn't directly supported yet, our WebSocket API serves as a versatile alternative, ensuring you can still harness the power of our Streaming STT service.

Enhancing Transcription Accuracy

Understanding that every audio stream is unique, we offer the ability to customize your transcription experience. By specifying audio encoding settings and adding custom vocabulary, you can significantly boost the probability of accurate transcriptions. Additionally, our service allows for the manual ending of utterances and the configuration of utterance detection thresholds, providing you with greater control over how your audio content is transcribed.

In summary, AssemblyAI's Streaming Speech-to-Text service is a robust, real-time transcription solution designed to meet the needs of modern professionals. By offering high accuracy, low latency, and customizable features, it stands as a pivotal tool in the realm of digital transcription services. Whether you're looking to transcribe live meetings, podcasts, or any streaming audio, AssemblyAI is poised to elevate your transcription capabilities to new heights.

Streaming Speech-to-Text: An Overview

Streaming Speech-to-Text (STT) technology presents an innovative approach to transcribing live audio with remarkable precision and minimal delay. This advanced solution empowers users to stream their auditory content directly to a secure WebSocket API, ensuring the swift return of text transcripts within milliseconds. The technology is designed to cater to real-time applications, providing an efficient and seamless transcription experience.

Key Features

High Accuracy and Low Latency

One of the cornerstone features of Streaming STT is its ability to deliver highly accurate transcripts with minimal latency. Users can expect to receive their transcriptions back in just a few hundred milliseconds, making it an ideal solution for applications that require immediate text output from spoken word.

Secure WebSocket API

The backbone of this technology is its secure WebSocket API, which facilitates a stable and secure connection for streaming audio data. This ensures not only the integrity and confidentiality of the audio content but also a reliable transcription process free from interruptions.

English Language Support

Currently, Streaming STT is tailored specifically for the English language. This focus allows for the refinement and optimization of the transcription process, ensuring superior accuracy and performance for English-speaking users. For information on supported languages and potential updates, users are encouraged to consult the 'Supported Languages' section.

Getting Started with Streaming STT

To harness the power of Streaming Speech-to-Text, users can begin by exploring the official SDKs provided. These SDKs are available for a variety of programming languages, including Python, JavaScript/TypeScript, Go, and Java. For those whose preferred language is not yet supported, guidance is provided on utilizing the WebSocket API directly.

Supported Programming Languages

  • Python: A widely used language that offers simplicity and flexibility for various applications.
  • JavaScript / TypeScript: Ideal for web developers looking to integrate STT into their web applications.
  • Go: Known for its efficiency and performance, suitable for high-speed transcription needs.
  • Java: Offers cross-platform capabilities, making it a versatile choice for diverse environments.

For detailed instructions on getting started with each SDK, users are directed to the 'Getting Started Guides' section, which provides comprehensive step-by-step guides for each supported programming language.


Streaming Speech-to-Text by AssemblyAI stands out as a cutting-edge solution for transcribing live audio streams efficiently and accurately. Its low latency, high accuracy, secure data transmission, and support for the English language make it a top choice for developers and organizations looking to leverage real-time transcription capabilities. By following the guidelines provided in the official SDKs, users can easily integrate this technology into their applications, enhancing the accessibility and usability of their audio content.


In the fast-paced world of technology, the capability to transcribe audio content in real-time opens up a plethora of opportunities across various sectors. AssemblyAI's Streaming Speech-to-Text (STT) service is at the forefront of this innovation, offering users the ability to convert live audio streams into text with remarkable accuracy and minimal delay. This service, tailored specifically for the English language, leverages a secure WebSocket API to deliver transcripts in just a few hundred milliseconds.

Supported Languages

Currently, the Streaming Speech-to-Text feature is exclusively available for English. This focus allows for the refinement and optimization of transcription services for the most widely used language on the internet, ensuring high accuracy rates and efficient processing.

Getting Started

Embarking on the journey with AssemblyAI's Streaming STT is straightforward. Official SDKs are available for major programming languages including Python, JavaScript/TypeScript, Go, and Java, designed to cater to a broad developer audience. For those working with other languages, detailed documentation on the WebSocket API is provided to facilitate integration.

Audio Requirements

To ensure optimal transcription accuracy, audio streams must adhere to specific formats. Supported encodings include PCM16 or Mu-law, with a necessity for the audio sample rate to match the specified sample_rate parameter. Single-channel audio segments, ranging from 100 to 2000 milliseconds in length, are required, with a sweet spot between 100 ms and 450 ms for the best transcription outcomes.

Specify the Encoding

The system defaults to PCM16 encoding, but flexibility is offered through the option to switch to Mu-law encoding by setting the relevant parameter. This adaptability allows users to tailor the transcription process to their specific audio sources.

Add Custom Vocabulary

Enhancing transcription accuracy for specialized or niche content is achievable by adding custom vocabulary. Users can input up to 2500 characters of tailored vocabulary to increase the likelihood of these terms being accurately transcribed, thereby customizing the service to suit their unique needs.

Authenticate with a Temporary Token

Security is paramount, and to this end, AssemblyAI provides a method for client-side authentication without exposing the API key. This is achieved through the generation of temporary authentication tokens, which can be used for single WebSocket sessions, offering both security and convenience.

Manually End Current Utterance

Control over the transcription process is further enhanced by the ability to manually end an utterance. This feature allows users to immediately produce a final transcript, providing flexibility in managing the flow of speech-to-text conversion.

Configure the Threshold for Automatic Utterance Detection

Fine-tuning the transcription service is possible by configuring the silence threshold for ending an utterance. Users can adjust this threshold at any point during a session, allowing for dynamic adaptation to varying speech patterns and ensuring transcripts accurately reflect the intended pauses in speech.

By providing a comprehensive suite of features, AssemblyAI's Streaming Speech-to-Text service represents a significant advancement in real-time audio transcription technology. Whether for transcribing meetings, phone calls, or live broadcasts, this service offers an efficient, accurate, and flexible solution for converting speech to text.

Streaming with AssemblyAI in Python

In the world of real-time audio processing and transcription, AssemblyAI stands out with its Streaming Speech-to-Text (STT) capabilities. This guide will walk you through the essentials of setting up a Python application to stream audio to AssemblyAI for real-time transcription. Our focus is on clarity, simplicity, and effectiveness, ensuring you can integrate this powerful functionality into your projects seamlessly.


Before diving into the code, ensure that you have Python installed on your system. You'll also need to sign up for an AssemblyAI account to obtain your API key, which is crucial for authenticating and utilizing their services.

Setting Up Your Python Environment

To get started, create a new Python virtual environment to keep your project dependencies isolated. You can do this by running:

python3 -m venv assemblyai-env
source assemblyai-env/bin/activate

Next, install the WebSocket client library, as it is essential for establishing a connection to AssemblyAI's WebSocket API for streaming audio data in real-time.

pip install websocket-client

Establishing a WebSocket Connection

To interact with AssemblyAI's real-time transcription service, you'll need to establish a secure WebSocket connection. Here's how you can achieve that:

import websocket

def create_connection():
    ws = websocket.WebSocket()
               header={"Authorization": "Bearer YOUR_API_KEY"})
    return ws

Replace YOUR_API_KEY with your actual AssemblyAI API key. The sample_rate parameter should match the sample rate of your audio stream.

Streaming Audio Data

Once the connection is established, streaming audio data is straightforward. You'll need to encode your audio in PCM16 or Mu-law format and send it through the WebSocket connection. AssemblyAI recommends sending audio segments between 100 ms and 450 ms for optimal transcription accuracy.

Handling Transcriptions

As you stream audio data, AssemblyAI's API will send back real-time transcriptions. Here's a simple way to handle these incoming messages:

def receive_transcriptions(ws):
    while True:
        result = ws.recv()
        print("Received transcription:", result)

This function listens for incoming messages (transcriptions) and prints them out. You can modify this function to process the transcriptions according to your application's needs.

Finalizing the Connection

Don't forget to properly close the WebSocket connection once your streaming session is complete to free up resources.

def close_connection(ws):


Integrating real-time audio transcription into your Python applications with AssemblyAI is both powerful and straightforward. By following the steps outlined in this guide, you can start harnessing the power of AI to transcribe live audio streams accurately and efficiently, opening up a myriad of possibilities for your projects.

Remember, this guide is just the beginning. Explore AssemblyAI's documentation and resources to unlock the full potential of their speech-to-text capabilities in your applications.


In the rapidly evolving landscape of digital communication, the ability to accurately and efficiently transcribe audio content in real time has become a cornerstone for enhancing accessibility and engagement. AssemblyAI's Streaming Speech-to-Text (STT) service stands at the forefront of this technological revolution, offering an unparalleled solution that combines high precision with minimal latency. This service not only opens new avenues for content creators and businesses to connect with their audience but also paves the way for innovations in how we interact with and process spoken information.

Key Takeaways

High Accuracy and Low Latency

The hallmark of AssemblyAI's Streaming STT is its exceptional accuracy coupled with swift transcription speeds. By leveraging advanced algorithms and a secure WebSocket API, users can expect transcripts within mere milliseconds of audio streaming, ensuring that the essence of the spoken word is captured with minimal delay.

Custom Vocabulary Enhancement

A standout feature of this service is the ability to tailor transcriptions through the addition of custom vocabulary. This functionality significantly boosts the probability of correctly transcribing specialized terms and phrases, making the service adaptable to various industries and niches.

Secure Authentication

Security and privacy concerns are adeptly addressed with the option for temporary authentication tokens. This feature ensures that user credentials remain protected while still providing seamless access to the service's capabilities.

Utterance Control

Users are granted meticulous control over the transcription process, with the ability to manually end utterances or adjust the silence threshold for automatic detection. This level of customization enhances the flexibility and applicability of the service across different audio environments.

Future Perspectives

As we look to the future, the potential applications for Streaming Speech-to-Text technology are boundless. From transforming educational settings to enabling more dynamic and interactive customer service experiences, the ability to transcribe audio accurately and instantaneously will continue to play a pivotal role. AssemblyAI's commitment to innovation and excellence ensures that as the demands of digital communication evolve, so too will the capabilities of their Streaming STT service.

In conclusion, AssemblyAI's Streaming Speech-to-Text service is not just a tool but a gateway to unlocking the full potential of audio content. Its impact on creating more accessible, engaging, and efficient digital communications cannot be overstated. As we embrace this technology, we step into a future where the barriers between spoken words and written text are seamlessly bridged, opening up a world of possibilities for creators, businesses, and audiences alike.