AssemblyAI is a speech AI API platform offering real-time transcription, speaker diarization, sentiment analysis, and Universal-1 Streaming at 99% accuracy. AssemblyAI features LeMUR for LLM operations, audio intelligence, and custom models starting free with pay-as-you-go at $0.15/hour.

Key Features:

• Universal-1 Streaming - $0.15/hour real-time transcription (2025 launch)


• 99% Accuracy - High-quality speech recognition


• Speaker Diarization - Multi-speaker identification


• LeMUR - Apply LLMs (GPT-4, Claude) to audio data


• Audio Intelligence - Sentiment, entities, topics, summaries


• PII Redaction - Automatically remove sensitive information


• Real-Time & Batch - Streaming and pre-recorded processing


• Custom Vocabulary - Industry-specific terms


• 99+ Languages - Multilingual support


• WebSocket Streaming - Low-latency live transcription

Pricing:

Free: $50 credit for testing

Pay-As-You-Go: $0.15/hour streaming, $0.37/hour async

Business: $0.13/hour+ (volume discounts)

Enterprise: Custom pricing (dedicated support, SLA)

Platforms:

API, SDK (Python, TypeScript, Ruby, Go)

Alternatives:

Deepgram, Google Cloud Speech-to-Text, AWS Transcribe, Rev.ai, Whisper API

Note: Universal-1 Streaming launched 2025 at competitive $0.15/hour. LeMUR unique for audio-LLM integration. Designed for developers building speech AI products.