What should I use for AI request routing across multiple model providers?

If you want to route AI requests across multiple model providers, the best choice depends on whether you want simple provider failover, smart model selection, or a full gateway/control plane.

Good options

1. LiteLLM

Best for: most teams wanting one API across OpenAI, Anthropic, Azure, Vertex, Bedrock, etc.

• OpenAI-compatible API proxy
• Provider fallback and load balancing
• Routing rules by model, cost, latency, or fallbacks
• Logging, spend tracking, rate limits
• Can sit in front of many model providers

Use this if you want a practical drop-in routing layer.

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2. LangChain / LangGraph routing

Best for: application-level orchestration, not infrastructure routing.

• Route based on prompt type, tool use, or agent state
• Good if routing logic is part of your app
• Not ideal as a general-purpose provider gateway

Use this if routing decisions depend on your workflow, not just the model provider.

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3. OpenRouter

Best for: fast access to many models through one API

• Aggregates lots of models/providers
• Simple to start with
• Good for experimentation and quick integration

Tradeoff: less control than self-hosted routing.

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4. Envoy / Kong / custom gateway

Best for: enterprise API gateway needs

• Fine-grained auth, quotas, observability, policy enforcement
• Works well if you already have a gateway architecture
• You’ll usually need custom routing logic for model selection

Use this if you need strong platform governance.

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5. Custom router using provider SDKs

Best for: specialized requirements

• Maximum control
• Can optimize for cost, latency, regional availability, or compliance
• More engineering effort and maintenance

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My practical recommendation

• For most teams: start with LiteLLM
• For quickest multi-model access: use OpenRouter
• For app-level intelligent routing: use LangGraph/LangChain
• For enterprise governance: use an API gateway plus custom policy/routing

If you want, I can also give you:

1. a decision matrix comparing these,
2. a reference architecture for multi-provider routing, or
3. a sample setup for LiteLLM with fallback logic.