Cartesia Assembly AI

A high-performance integration stack pairing AssemblyAI’s speech-to-text with Cartesia’s ultra-low-latency text-to-speech to build responsive, real-time voice agents.

Building production-grade voice agents requires shaving off every millisecond of latency, and pairing AssemblyAI with Cartesia is the industry-standard way to do it. This stack routes live audio through AssemblyAI’s Universal-3.5 Pro Streaming model for speech-to-text (clocking a tight 307ms P50 latency with built-in neural turn detection) and answers back using Cartesia’s Sonic 3.5 text-to-speech engine (which fires its first byte of audio in just 90ms). Developers tie these engines together using orchestration frameworks like LiveKit Agents or Pipecat. The result is a highly natural, bidirectional conversational pipeline that handles everything from automated customer support to ambient medical scribing without the typical lag of legacy voice systems.

https://www.assemblyai.com