Lowest-Latency Inference APIs for Voice and Realtime Agents: A Time to First Token TTFT-First Benchmark

This article analyzes the latency involved in voice AI systems, focusing on the time to first token (TTFT) metric and its limitations. It benchmarks each stage of the voice stack—speech-to-text, language model inference, text-to-speech, and network delays—to understand the total latency affecting conversational naturalness.