We built 8 AI-powered SaaS products in 2025. Here is the exact stack, costs, and timeline for each. By David Friedman , Founder of AppBrewers AI is not a feature anymore. It is the product. We built 8 AI-powered SaaS products in 2025. Some failed. Three are profitable. Here is the exact stack, costs, and timeline that worked. What "AI-Powered SaaS" Means in 2026 Type AI Role Example Complexity AI wrapper UI around GPT-4 Writing assistant Low AI agent Multi-step reasoning Research assistant Medium AI copilot Context-aware suggestions Code reviewer Medium AI platform Custom models + training Image generator High AI automation Workflow execution Invoice processor Medium Tech Stack Layer Technology Cost Why Frontend Next.js 15 Free App Router, streaming, SEO Backend Next.js API routes / Firebase Free - 200 Euro Serverless, scalable AI model OpenAI GPT-4o / Claude 3.5 20-500 Euro/month Best reasoning, fastest Vector DB Pinecone / Weaviate / Supabase 0-100 Euro/month RAG, semantic search Auth Firebase Auth / Clerk…