How to use one OpenAI-compatible gateway for chat, responses, embeddings, rerank, image, and audio APIs

If you're building an AI-powered app today, you're probably juggling multiple model providers. OpenAI for GPT. DeepSeek for cost savings. A Chinese model for specific tasks. Maybe Anthropic for Claude. Each provider has its own SDK, its own auth flow, its own quirks. That's not just annoying—it's fragile. Switching models means rewriting code. Adding a new provider means more maintenance burden. There's a cleaner approach: one gateway that speaks OpenAI's protocol, but routes to multiple backend