AI Application-Layer Startup Radar2026. 05. 22. 20:01:57AI Application-Layer Startup Radar — Week of May 16–22, 2026Five AI application-layer companies — Sierra, EliseAI, Blitzy, Hightouch, and Vapi — raised a combined $1.6B this week. Covers round sizes, post-money valuations, lead investors, and founder backgrounds for each deal.