When building conversational agents or real-time voice applications, latency is the defining metric. If Time-to-First-Byte (TTFB) exceeds 200ms, natural turn-taking breaks down and conversational interruption becomes clunky. We recently recorded and aggregated median latency and pricing metrics across the primary streaming Text-to-Speech APIs using WebSocket connections (US-East endpoints, median across 1,000 requests). Summary Table Provider Model TTFB Latency Pr...