FreeAPIHub
HomeAPIsAI ModelsAI ToolsBlog
Favorites
FreeAPIHub

The central hub for discovering, testing, and integrating the world's best AI models and APIs.

Platform

  • Categories
  • AI Models
  • APIs

Company

  • About Us
  • Contact
  • FAQ

Help

  • Terms of Service
  • Privacy Policy
  • Cookies

© 2026 FreeAPIHub. All rights reserved.

GitHubTwitterLinkedIn
  1. Home
  2. Categories
  3. Speech & Audio
  4. AssemblyAI
published AI Powered

AssemblyAI

AssemblyAI offers developers a powerful API for transcribing audio and video, featuring speaker diarization, sentiment analysis, and LLM-powered summaries.

Developed by AssemblyAI Inc.

Live API
99.90%Uptime
800msLatency
3.5kStars
API KeyAuth
NoCredit Card
RESTStyle
v2Version

Reference

API Endpoints

Endpoints

Available routes, request structures, and code examples.

Transcribes audio files to text with speaker diarization

Endpoint URL
https://api.assemblyai.com/transcript
Code Example
curl -X POST 'https://api.assemblyai.com/transcript' \
  -H 'Authorization: Bearer YOUR_API_KEY'
Request Payload
{
  "audio_url": "https://example.com/audio.mp3",
  "speaker_labels": true
}
Expected Response
{
  "id": "abc123",
  "text": "Hello world this is a test",
  "words": [
    {
      "end": 0.8,
      "word": "Hello",
      "start": 0.5,
      "speaker": "A"
    }
  ],
  "status": "completed"
}
Version:v2
Limit:300 minutes/month

Integration

Quick Start

cURL ExampleREST
curl -X GET "https://api.assemblyai.com/v2/transcript"

Docs

Technical Documentation

What this API does

AssemblyAI provides a robust speech-to-text API that transforms audio and video content into accurate, searchable text. Key features include speaker diarization for identifying different speakers, sentiment analysis for understanding emotional tone, and large language model powered summaries that condense lengthy transcripts.

How it works

Developers can upload pre-recorded audio and video files or stream live audio for transcription. The API supports RESTful endpoints, returning responses in JSON format to facilitate integration with various programming environments. This API is adaptable for applications in media, customer service, and healthcare.

Authentication

To access the AssemblyAI API, developers need to sign up for an API key. This key must be included in the headers of API requests for authentication and tracking.

Example usage

  • POST /v2/transcript - Submits audio or video for transcription.
  • GET /v2/transcript/{id} - Retrieves the transcription result based on the transcript ID.
  • POST /v2/diarize - Requests speaker diarization on an audio file.

Limits

Limits on transcription duration and request frequency may apply; however, specific values are not documented. It's advisable to monitor usage to avoid exceeding any unspecified limits.

Ideal use cases

  • Building applications for media transcription and analysis.
  • Creating customer support tools that analyze call sentiments.
  • Developing educational platforms with transcribed lectures.
  • Integrating voice-to-text features in healthcare applications.

Examples

Real-World Applications

  • Automated transcription for podcasts and videos
  • Customer support call sentiment analysis
  • Voice-enabled healthcare documentation
  • Meeting and conference transcription with speaker identification
  • Generating concise summaries of lengthy audio content

Evaluation

Advantages & Limitations

Advantages
  • ✓ High transcription accuracy with advanced speech recognition
  • ✓ Supports speaker diarization and sentiment analysis
  • ✓ LLM-powered summaries for quick content understanding
  • ✓ Flexible input via file upload or live streaming
  • ✓ Comprehensive SDKs and detailed documentation
Limitations
  • ✗ Limited support for non-English languages
  • ✗ Pricing can be high for large-scale usage
  • ✗ Requires internet connectivity for API access
  • ✗ No built-in support for on-premise deployment

Support

Frequently Asked Questions

Important Notice

Verify Before You Decide

Last verified · Apr 30, 2026

The details on this page — including pricing, features, and availability — are based on our last review and may not reflect the provider's current offering. Providers update their products frequently, sometimes without prior notice.

What may have changed

Pricing Plans
Features & Limits
Availability
Terms & Policies

Always visit the official provider website to confirm the latest pricing, terms, and feature availability before subscribing or integrating.

Check official site

External Resources

Documentation Official Website Pricing Details Postman Collection

API Specifications

v2
Pricing Model
Pay-as-you-go
Credit Card
Not Required
Response Formats
JSON
Supported Languages
6 Languages
SDK Support
Python, JavaScript, Ruby, Go
Rate Limit

1000 requests per minute

Time to Hello World

Less than 1 hour

Free Tier

$50 in free credits valid for 30 days; no credit card required to start

Best For

Developers building transcription, voice analytics, and content summarization apps

Not Ideal For

Projects requiring extensive offline or on-premise speech processing

Tags

#speaker-diarization#assemblyai#real-time#Transcription#audio#nlp#speech-to-text

You Might Also Like

More APIs Similar to AssemblyAI

Google Cloud Speech-to-Text API

The Google Cloud Speech-to-Text API provides developers with free audio transcription capabilities, enabling the conversion of audio into text across 125+ languages.

public AIREST

Async.ai TTS API

The Async.ai TTS API offers developers free access to a robust text-to-speech solution with advanced voice cloning and multilingual capabilities, making it ideal for enhancing user engagement.

public AIREST

Quran API

The Quran API offers developers free and seamless access to the complete Quranic text, translations, and verse-level metadata, suitable for apps and educational tools.

publicREST