10 Best Speech to Text APIs

Discover the power of speech recognition with our top picks for the 10 best speech to text APIs.

Speech to text technology has changed how we interact with devices, making digital communication faster and more accessible. With so many options on the market, choosing the right one can be overwhelming. In this article, we’ll break down the 10 best speech to text APIs available so you can find the perfect fit for your project.

What to Look for in a Speech to Text API

A speech to text API converts spoken words into written text, offering a range of functionalities important for accessibility, documentation, and transcription services. To harness the full potential of this technology, here are some important aspects to look for when choosing a speech to text API:

• Accuracy: The speech to text API should deliver high transcription accuracy, even in environments with background noise or multiple speakers.
• Language Support: Look for a speech to text API that supports a wide range of languages and dialects to cater to a global audience.
• Real-time Processing: The speech to text API should be capable of transcribing speech in real-time, which is crucial for applications like live captioning and voice-driven control systems.
• Ease of Integration: The speech to text API should be easy to integrate with existing systems and support common programming languages and platforms.
• Cost-effectiveness: Evaluate the pricing structure to ensure the speech to text API aligns with your usage expectations and budget constraints.
• Security and Privacy: The speech to text API provider should adhere to strict data security and privacy standards to protect sensitive information.
• Latency: Low latency is essential for a smooth user experience, particularly when using the speech to text API to create interactive applications.

Top 10 Best Speech to Text APIs

From real-time transcription services in journalism and automated captioning in video streaming to voice-driven control systems in smart homes and interactive customer support tools, the right speech to text API can transform operations and enhance accessibility. Whether you're a developer looking to add voice functionality to your app or a business aiming to improve user experience, speech to text APIs offer powerful and adaptable solutions. Let’s explore the top 10 speech to text APIs based on features, accuracy, and language support so you can find the perfect fit for your unique needs:

Amazon Transcribe

Amazon Transcribe is known for its high accuracy in transcribing both streaming and recorded speech, trained across millions of hours of audio and supporting more than 100 languages. It includes features like automatic punctuation, custom vocabularies, and vocabulary filters, alongside automatic speaker and language detection. It also provides word-level confidence scores, content moderation, and sensitive information redaction. Additionally, Amazon Transcribe can automatically extract insights such as sentiment, call categories, and characteristics, and generate AI-powered summaries, making it a comprehensive tool for transcribing call analytics.

IBM Watson Speech to Text

IBM Watson Speech to Text offers high accuracy and can be tailored to your specific domain language and characteristics. It is deployable across various environments, including public, private, hybrid, multi-cloud, and on-premises setups. It boasts low latency, supports 31 languages, and provides audio diagnostics to correct weak signals before transcription begins. While Watson Speech to Text’s speaker diarization is optimized for two-way call center conversations, it can detect up to six different speakers. The API also offers smart formatting of dates, times, numbers, and addresses, enhancing the readability and accuracy of the transcriptions as well as word filtering for its US users.

Microsoft AI Azure Speech

Microsoft AI Azure Speech excels in providing real-time transcription, fast synchronous transcription, and batch processing for large volumes of pre-recorded speech. It offers custom speech options to enhance accuracy for specific domains and supports transcriptions, captions, and subtitles for live meetings. Additional features include speaker diarization, pronunciation assessment, and a variety of tools to assist call center agents. Microsoft's Azure Speech supports 85 languages and variants and is accessible through multiple interfaces like Speech SDK, Speech CLI, and Speech to Text REST API.

Google Cloud Speech to Text

Google Cloud Speech to Text is an advanced API supporting over 125 languages, designed to enhance transcription accuracy by adapting its model to recognize frequently used words more effectively. For example, users can set the API to favor between homophones like “whether” or “weather.” It also offers three flexible speech recognition methods—synchronous, asynchronous, and real-time streaming—to accommodate a variety of application needs. With competitive pricing at $0.024 or $0.016 per minute, this API is ideal for developers in media, customer service, and education sectors looking for a reliable and cost-effective STT solution.

Deepgram

Deepgram supports 36 languages and offers over 90% accuracy with less than 300ms latency, making it ideal for real-time applications such as live broadcasts and customer service interactions. The Deepgram speech to text API offers lower word error rates and costs compared to competitors like Amazon Transcribe. Deepgram's smart formatting enhances readability by automatically adding punctuation and paragraphs, while its ability to autodetect speaker changes and redact sensitive information ensures both privacy and clarity in transcriptions. This combination of features makes Deepgram a powerful tool for organizations requiring fast and reliable speech to text services.

Rev.ai

Rev.ai provides asynchronous transcription services in over 58 languages and supports real-time streaming for audio and video in 9 languages. This service excels in its language identification capabilities and, for English content, offers additional features such as sentiment analysis, topic extraction, and summarization. Rev.ai also provides context-aware translations in 11 languages, catering to global businesses and multilingual events. Its precise timestamps for English, Spanish, and French ensure that transcriptions are easy to follow and synchronize with original content, making Rev.ai a versatile and powerful tool for a wide range of transcription needs. Additionally, Rev’s API has a low word error rate compared to its competition when looking at ethnic background, nationality, gender, and accent.

AssemblyAI

AssemblyAI features advanced speaker diarization technology and automatically formats text and alphanumerics, providing clear and structured transcripts. It captures multilingual speech with high accuracy (>93%) and includes automatic language detection, which is vital for processing content in diverse linguistic environments. With a latency of 30.4 seconds and training on 12.5 million hours of multilingual data, AssemblyAI supports over 99 languages. It offers detailed word-by-word timestamps, profanity filtering, and the ability to adjust custom vocabularies and spellings, making it ideal for a variety of professional settings, including legal, medical, and educational fields.

Speechmatics

Speechmatics processes an equivalent of 500 years of audio monthly, supporting over 50 languages. This service delivers Automatic Speech Recognition (ASR) in less than one second and is rigorously tested in real-world noisy environments, ensuring high accuracy and low latency across a variety of audio conditions. Speechmatics is designed to be robust against background noise and different accents, providing reliable transcriptions even in challenging situations. This makes it particularly suitable for media, emergency services, and public speeches, where clarity and speed are crucial.

OpenAI

OpenAI's speech to text API handles files up to 25MB, transcribing audio in the language it is presented in, and offering the option to translate and transcribe the audio into English. Supporting 66 languages, it provides detailed timestamps, which are essential for accurate syncing in subtitles and detailed documentation. OpenAI uses prompts to improve the quality of the transcripts, which is especially useful for ongoing and completed audio recordings, such as interviews and conferences. This service is particularly beneficial for creators and professionals who require dependable and versatile transcription tools.

ElevenLabs

ElevenLabs supports 99 languages and offers unique features such as character-level timestamps and automatic speaker detection, which greatly enhance the detail and utility of transcriptions. It also includes audio-event tagging, further enriching the context of transcriptions for better content analysis. ElevenLabs offers a low word error rate with a 97% accuracy rate in English and 98% in major languages, significantly reducing errors in languages that are often underserved by other platforms, such as Serbian, Cantonese, and Malayalam. This makes ElevenLabs particularly valuable for global enterprises and multilingual service providers needing reliable and inclusive transcription services.

How Speech To Text APIs are Different than Text To Speech APIs

Speech to text APIs and text to speech APIs fulfill complementary roles in the field of voice technology. Speech to text APIs convert spoken language into written text, which is crucial for enabling features such as voice-controlled applications and automated transcription services. On the other hand, text to speech APIs like Speechify Text to Speech API transform written text into spoken audio, which is essential for developing accessibility apps and interactive customer support systems. 

For example, Speechify offers sub-300ms latency to deliver near-instant audio output that mimics human-like quality across all supported languages. It also features a wide emotional range with 13 different emotions, making it ideal for developing conversational AI, AI voice agents, creating voice overs for videos, and narrating content.