Smallest AI

AssemblyAI is a voice AI infrastructure platform that provides APIs and models for transcribing, understanding, and interacting with speech. Its products include pre-recorded, realtime, and synchronous speech-to-text APIs; speech understanding for capabilities such as speaker identification, sentiment, chapters, and summaries; inline audio and transcript guardrails; an LLM Gateway with fallback; and a Voice Agent API with turn detection and interruption handling. The platform can combine speech-to-text, an LLM, and text-to-speech into a real-time voice-agent stack, and supports voice applications such as notetakers, call analytics, medical transcription, dictation, agent assist, and AI scribes. AssemblyAI states that its speech-to-text APIs support 99 languages and that its infrastructure processes about 2 million hours of audio per day.

AssemblyAI's Voice Agent API is an API for building real-time voice agents. It connects speech-to-text, an LLM, and text-to-speech through a single WebSocket, with built-in turn detection and interruption handling.

An AI voice-agent platform for building and deploying phone-based conversational agents. It supports agents that conduct automated interviews and other business conversations over telephone calls.

Hydra is a speech-to-speech AI model from Smallest AI for asynchronous speech input and output, with support for text and tool calls.

Speechify is an AI voice and text-to-speech platform that reads written material aloud and also provides speech-to-text, conversational, and business-focused AI tools. Its SpeechifyAI service offers text-to-speech and realtime voice-agent APIs through a single interface, with streaming synthesis, zero-shot voice cloning from a consented reference clip, SSML-based emotion control, and multilingual output for English, German, Mexican Spanish, French, Italian, and Brazilian Portuguese. The service includes the Simba model family, which the site describes as streaming-native speech models designed to model voice identity, expression, and language for realtime conversation. Speechify was co-founded by Cliff Weitzman, who initially built it to consume written material through audio.