Retell AI
Platform for building production voice agents with sub-800ms latency end-to-end. Handles telephony, turn-taking, backchannels, and interruptions natively. Strong on call reliability and HIPAA compliance for healthcare use cases.
ElevenLabs
State-of-the-art TTS API with voice cloning, multilingual support, and low-latency streaming. Used in podcasts, audiobooks, conversational AI agents, and game NPCs.