One API Key for GPT, Claude, Gemini, and Qwen: A Practical Guide to OpenAI-Compatible Model Routing

Short summary

An OpenAI-compatible API gateway enables your application to route requests across multiple LLM providers (GPT, Claude, Gemini, Qwen) using a single SDK and consistent interface, requiring only baseURL, apiKey, and model changes. Implement task-specific routing logic to reserve expensive reasoning models for high-value tasks, use cheaper models for summarization and extraction, and add automatic fallbacks between providers for reliability. This architectural pattern eliminates the need to maintain provider-specific SDKs, simplifies testing new models, and reduces API spend by matching model cost to task requirements.

• •Route requests across multiple LLM providers through a single OpenAI-compatible interface
• •Use task-specific logic to optimize model selection by cost and quality
• •Add fallback patterns for reliability when providers are slow or unavailable

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