Building a Multi-LLM Fallback System with Vercel AI SDK

A practical guide to implementing LLM provider fallback chains for production applications. Covers the architecture of Geonapse's 3-tier fallback system (Gemini Flash-Lite ? Groq ? DeepSeek), error handling patterns, cost optimization strategies, response quality validation, and monitoring. Includes code examples using Vercel AI SDK's unified interface and lessons learned from running multi-provider LLM systems in production.