Multi-Provider Failover and Load Balancing: Surviving LLM Provider Outages

Production LLM applications depend on third-party providers with real outages, 429 rate-limit storms, and p99 latency spikes, making any single provider a potential single point of failure. Failure modes differ and require different responses: hard 5xx errors, 429 rate limits with provider-specific Retry-After headers, latency degradation, partial streaming failures, and content-filter rejections. The article covers multi-provider failover and load balancing strategies to keep AI applications resilient across LLM provider incidents.