A unified API for AI model routing

Google Cloud API Gateway has introduced model routing in Public Preview, enabling developers to route OpenAI-compatible requests to Gemini, Claude, or OpenAI OSS-GPT models via a serverless ingress layer. The feature allows dynamic routing based on rules defined in an OpenAPI spec, with support for rate limiting and token tracking, and can be integrated with the Gemini Enterprise Agent Platform for security governance.

When building AI applications, developers need the freedom to route traffic to the best model for the job without hardcoding endpoints or managing open-source proxies. Google Cloud API Gateway https://docs.cloud.google.com/api-gateway/docs now offers model routing in Public Preview to solve this. It provides a lightweight, serverless ingress layer that accepts OpenAI-compatible requests and dynamically routes them to Gemini, Claude, or OpenAI OSS-GPT. API Gateway can be used standalone for simple rate limiting and token tracking, or paired seamlessly with the Gemini Enterprise Agent Platform. For example, you can route your agent's egress through Agent Gateway for strict security governance, and then pass the request to API Gateway to handle dynamic routing to Google-hosted LLMs. Here is a step-by-step guide on how to configure your routing logic. Setting up your model routing logic takes just a few steps: x-google-api-management extension block. openapi: 3.0.4 info: title: OpenAPI 3.x spec using Model Routing description: Using Model Routing in an OAS 3.x spec version: 1.0.0 x-google-api-management: backends: gemini-35-flashlite: address: - https://aiplatform.googleapis.com/v1/projects/YOUR PROJECT ID/locations/global/publishers/google/models/gemini-3.5-flash-lite:generateContent deadline: 60.0 pathTranslation: CONSTANT ADDRESS anthropic-claude-opus-47: address: - https://aiplatform.googleapis.com/v1/projects/YOUR PROJECT ID/locations/global/publishers/anthropic/models/claude-opus-4-7:rawPredict deadline: 60.0 pathTranslation: CONSTANT ADDRESS openai-gpt-oss-120b: address: - https://aiplatform.googleapis.com/v1/projects/YOUR PROJECT ID/locations/global/endpoints/openapi/chat/completions deadline: 60.0 pathTranslation: CONSTANT ADDRESS ai: models: routing: routers: Router 1: route between Gemini default and Claude. gemini-claude-router: defaultModel: backend: gemini-35-flashlite targetModel: google/gemini-3.5-flash-lite rules: - model: "claude-opus-4-7" backend: anthropic-claude-opus-47 targetModel: anthropic/claude-opus-4-7 Router 2: route between OpenAI GPT default and Gemini. openai-gemini-router: defaultModel: backend: openai-gpt-oss-120b targetModel: openai/gpt-oss-120b-maas rules: - model: "gemini-3.5-flash-lite" backend: gemini-35-flashlite targetModel: google/gemini-3.5-flash-lite servers: - url: "https://my-gateway-url.com" paths: /v1/chat/gemini-claude: post: summary: "Endpoint:defaults to Gemini & Claude as an option." operationId: "chatGeminiClaude" x-google-model-router: gemini-claude-router responses: '200': description: "OK" /v1/chat/openai-gemini: post: summary: "Endpoint:defaults to OpenAI & Gemini as an option." operationId: "chatOpenAIGemini" x-google-model-router: openai-gemini-router responses: '200': description: "OK" Note: All backends referenced by a single router must share the same host for example, aiplatform.googleapis.com . Routing selects a different model and path on that shared Vertex host — it does not route across different hosts. 2. Deploy the Gateway: Deploy your updated API config so the Gateway is active and ready to process traffic. 3. Send standard requests: Your application simply sends a standard OpenAI POST /v1/chat/gemini-claude or POST /v1/chat/openai-gemini request. The Gateway intercepts it, transcodes the payload to the native schema of the backend, and routes it on the fly. As an example use appropriate values for $API KEY and my-gateway-url.com : curl -X POST "https://my-gateway-url.com/v1/chat/gemini-claude" \ -H "content-type: application/json" \ -H "x-api-key: $API KEY" \ -d '{ "model": "claude-opus-4-7", "messages": {"role": "user", "content": "Introduce yourself in 5 words"} }' Model routing is now available in Public Preview for API Gateway. To stop managing proxies and start unifying your AI traffic, check out our documentation https://docs.cloud.google.com/api-gateway/docs/model-routing-overview to deploy your first model router today.