vercel-ai-gateway

name	vercel-ai-gateway
description	Set up Vercel AI Gateway (@ai-sdk/gateway) for multi-provider AI access. Use when adding the gateway, switching AI providers, handling reasoning/thinking models, or mocking AI in tests.
when_to_use	When building an AI app that needs multi-provider support, reasoning middleware, or test isolation via mock provider.
allowed-tools	Bash Read Write Edit

Vercel AI Gateway

@ai-sdk/gateway is a proxy layer that routes requests to multiple AI providers (OpenAI, Anthropic, Google, xAI, GROQ) under a single API key.

Your app → Vercel AI Gateway (cloud proxy) → OpenAI / Anthropic / Google / xAI

Vercel hosts the proxy — you connect provider accounts in their dashboard. On Vercel deployments: OIDC auto-auth, no key needed. Locally: set AI_GATEWAY_API_KEY.

Install

pnpm add @ai-sdk/gateway ai

Basic usage

import { gateway } from "@ai-sdk/gateway";

gateway.languageModel("google/gemini-2.5-flash-lite")
gateway.languageModel("anthropic/claude-haiku-4.5")
gateway.languageModel("openai/gpt-4o")

Model IDs follow <provider>/<model-name> format.

Reasoning / thinking models

Apply extractReasoningMiddleware to models that emit <thinking> tags:

import { gateway } from "@ai-sdk/gateway";
import { extractReasoningMiddleware, wrapLanguageModel } from "ai";

const THINKING_SUFFIX_REGEX = /-thinking$/;

export function getLanguageModel(modelId: string) {
  const isReasoning = modelId.includes("reasoning") || modelId.endsWith("-thinking");
  if (isReasoning) {
    return wrapLanguageModel({
      model: gateway.languageModel(modelId.replace(THINKING_SUFFIX_REGEX, "")),
      middleware: extractReasoningMiddleware({ tagName: "thinking" }),
    });
  }
  return gateway.languageModel(modelId);
}

Test mock with customProvider

Swap real models for mocks via an env flag (e.g. PLAYWRIGHT=True):

import { customProvider } from "ai";

export const myProvider = isTestEnvironment
  ? customProvider({
      languageModels: {
        "chat-model": mockChatModel,
        "title-model": mockTitleModel,
      },
    })
  : null;

export function getLanguageModel(modelId: string) {
  if (isTestEnvironment && myProvider) return myProvider.languageModel(modelId);
  return gateway.languageModel(modelId);
}

Env

AI_GATEWAY_API_KEY=    # not needed on Vercel (OIDC auto-auth)

References

• food-tour-sg lib/ai/providers.ts: https://github.com/phucbm/food-tour-sg/blob/main/lib/ai/providers.ts
• Vercel AI SDK docs: https://ai-sdk.dev/docs/ai-sdk-core/providers-and-models
• @ai-sdk/gateway package: https://www.npmjs.com/package/@ai-sdk/gateway