Last year I was the engineering lead at a B2B SaaS that was supposed to do "smart calling" for outbound sales teams. Click-to-call from the CRM, AI transcription, call routing based on lead score, the usual stack you'd expect in 2024. We chose a major CPaaS provider because nobody gets fired for picking the obvious one. The docs were great, the SDK worked in twenty minutes, and the pricing calculator told us we'd spend around $2,400 a month at our projected scale. Nine months later, we were burning $14,000 a month, our call quality was degrading during our biggest customer's peak hours, and I was on a call with a custom VoIP development company explaining why we needed to migrate. This is the story of what went wrong, what I should have caught earlier, and what I'd do differently if I were starting over. The first six months looked fine.…