The serverless hype has convinced half the SaaS world that servers are somehow "legacy tech" but I've migrated more companies away from serverless than to it this year. After architecting deployments for 25+ SaaS companies, here's what nobody talks about: serverless works great until it doesn't. And when it stops working, it stops working expensive. Last month I helped a client whose Vercel bill hit $8,000 for traffic that would cost $300 on a dedicated server. Their "infinitely scalable" architecture was bankrupting them during a successful product hunt launch. Those edge function invocations and bandwidth costs add up fast. Here's the reality check most founders need: When serverless actually makes sense: - Genuine spiky, unpredictable traffic (not "we might scale someday") - Simple, stateless functions that run fast - You have serious DevOps expertise on the team - Your margins can absorb 3-5x hosting costs When traditional servers win: - Predictable traffic patterns (most SaaS products) - Complex applications with shared state - Tight cost constraints (early stage startups) - You need to debug performance issues quickly The biggest lie about serverless is "no maintenance." You're still managing infrastructure, just with vendor specific tools instead of standard ones. And good luck debugging a cold start issue when your paying customers are waiting. I've seen too many teams choose Vercel because setting up a VPS "seemed complicated" then spend months wrestling with function timeouts and edge runtime limitations that would take an afternoon to solve on a regular server. The best architecture isn't the newest one. It's the one your team can actually operate without losing sleep. Your SaaS probably needs boring, predictable servers more than it needs infinite scale.