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Adapters

OpenRouter Adapter

OpenRouter is TanStack AI's first official AI partner and the recommended starting point for most projects. It provides access to 300+ models from OpenAI, Anthropic, Google, Meta, Mistral, and many more — all through a single API key and unified interface.

Installation

sh
npm install @tanstack/ai-openrouter
npm install @tanstack/ai-openrouter

Basic Usage

typescript
import { chat } from "@tanstack/ai";
import { openRouterText } from "@tanstack/ai-openrouter";
 
const stream = chat({
  adapter: openRouterText("openai/gpt-5"),
  messages: [{ role: "user", content: "Hello!" }], 
});
import { chat } from "@tanstack/ai";
import { openRouterText } from "@tanstack/ai-openrouter";
 
const stream = chat({
  adapter: openRouterText("openai/gpt-5"),
  messages: [{ role: "user", content: "Hello!" }], 
});

Configuration

typescript
import { createOpenRouterText } from "@tanstack/ai-openrouter";

const adapter = createOpenRouterText(
  "openai/gpt-5",
  process.env.OPENROUTER_API_KEY!,
  {
    serverURL: "https://openrouter.ai/api/v1", // Optional
    httpReferer: "https://your-app.com", // Optional, for rankings
    appTitle: "Your App Name", // Optional, for rankings
  },
);
import { createOpenRouterText } from "@tanstack/ai-openrouter";

const adapter = createOpenRouterText(
  "openai/gpt-5",
  process.env.OPENROUTER_API_KEY!,
  {
    serverURL: "https://openrouter.ai/api/v1", // Optional
    httpReferer: "https://your-app.com", // Optional, for rankings
    appTitle: "Your App Name", // Optional, for rankings
  },
);

Available Models

OpenRouter provides access to 300+ models from various providers. Models use the format provider/model-name:

typescript
model: "openai/gpt-5.1"
model: "anthropic/claude-sonnet-4.5"
model: "google/gemini-3-pro-preview"
model: "meta-llama/llama-4-maverick"
model: "deepseek/deepseek-v3.2"
model: "openai/gpt-5.1"
model: "anthropic/claude-sonnet-4.5"
model: "google/gemini-3-pro-preview"
model: "meta-llama/llama-4-maverick"
model: "deepseek/deepseek-v3.2"

See the full list at openrouter.ai/models.

Example: Chat Completion

typescript
import { chat, toServerSentEventsResponse } from "@tanstack/ai";
import { openRouterText } from "@tanstack/ai-openrouter";
 
export async function POST(request: Request) {
  const { messages } = await request.json();

  const stream = chat({
    adapter: openRouterText("openai/gpt-5"),
    messages, 
  });

  return toServerSentEventsResponse(stream);
}
import { chat, toServerSentEventsResponse } from "@tanstack/ai";
import { openRouterText } from "@tanstack/ai-openrouter";
 
export async function POST(request: Request) {
  const { messages } = await request.json();

  const stream = chat({
    adapter: openRouterText("openai/gpt-5"),
    messages, 
  });

  return toServerSentEventsResponse(stream);
}

Example: With Tools

typescript
import { chat, toolDefinition } from "@tanstack/ai";
import { openRouterText } from "@tanstack/ai-openrouter";
import { z } from "zod"; 

const getWeatherDef = toolDefinition({
  name: "get_weather",
  description: "Get the current weather",
  inputSchema: z.object({
    location: z.string(),
  }),
});

const getWeather = getWeatherDef.server(async ({ location }) => {
  return { temperature: 72, conditions: "sunny" };
});

const stream = chat({
  adapter: openRouterText("openai/gpt-5"),
  messages, 
  tools: [getWeather],
});
import { chat, toolDefinition } from "@tanstack/ai";
import { openRouterText } from "@tanstack/ai-openrouter";
import { z } from "zod"; 

const getWeatherDef = toolDefinition({
  name: "get_weather",
  description: "Get the current weather",
  inputSchema: z.object({
    location: z.string(),
  }),
});

const getWeather = getWeatherDef.server(async ({ location }) => {
  return { temperature: 72, conditions: "sunny" };
});

const stream = chat({
  adapter: openRouterText("openai/gpt-5"),
  messages, 
  tools: [getWeather],
});

Environment Variables

Set your API key in environment variables:

sh
OPENROUTER_API_KEY=sk-or-...
OPENROUTER_API_KEY=sk-or-...

Model Routing

OpenRouter can automatically route requests to the best available provider:

typescript
const stream = chat({
  adapter: openRouterText("openrouter/auto"),
  messages,
  modelOptions: {
    models: [
      "openai/gpt-4o",
      "anthropic/claude-3.5-sonnet",
      "google/gemini-pro",
    ],
  },
});
const stream = chat({
  adapter: openRouterText("openrouter/auto"),
  messages,
  modelOptions: {
    models: [
      "openai/gpt-4o",
      "anthropic/claude-3.5-sonnet",
      "google/gemini-pro",
    ],
  },
});

Chat Completions vs Responses (beta)

OpenRouter exposes two OpenAI-compatible wire formats, and the adapter package ships one of each:

AdapterEndpointStatusWhen to use
openRouterText/v1/chat/completionsStableDefault for almost everything. Broadest model + tool support.
openRouterResponsesText/v1/responsesBetaOpenAI Responses-shaped request/response; richer multi-turn state on OpenAI-style models.

Both adapters route to any underlying model OpenRouter supports (anthropic/..., google/..., meta-llama/..., etc.) — the wire format describes how your client talks to OpenRouter, not which provider answers. /v1/responses is OpenAI's newer API surface; OpenRouter implements it so clients that prefer that wire format can use it across the same 300+ model catalogue.

typescript
import { chat } from "@tanstack/ai";
import { openRouterResponsesText } from "@tanstack/ai-openrouter";

const stream = chat({
  adapter: openRouterResponsesText("anthropic/claude-sonnet-4.5"),
  messages: [{ role: "user", content: "Hello!" }],
});
import { chat } from "@tanstack/ai";
import { openRouterResponsesText } from "@tanstack/ai-openrouter";

const stream = chat({
  adapter: openRouterResponsesText("anthropic/claude-sonnet-4.5"),
  messages: [{ role: "user", content: "Hello!" }],
});

Caveats while the Responses adapter is in beta:

  • Function tools are supported; OpenRouter's branded server-tools (web search, file search, …) are not yet wired through this path — use openRouterText if you need those.
  • If in doubt, prefer openRouterText. The Chat Completions endpoint has broader provider coverage and feature parity today.

Next Steps

Provider Tools

Migrated from createWebSearchTool? This factory was renamed to webSearchTool and moved to the /tools subpath in this release. See Migration Guide §6 for the exact before/after.

OpenRouter's gateway exposes web search via a plugin that works across any proxied chat model. Import it from @tanstack/ai-openrouter/tools.

For the full concept, a comparison matrix, and type-gating details, see Provider Tools.

webSearchTool

Adds web search capability to any OpenRouter-proxied chat model. The factory accepts OpenRouter's WebSearchConfig directly — pick the engine (auto, native, exa, firecrawl, or parallel), cap results with maxResults / maxTotalResults, restrict which sites can appear in results with allowedDomains / excludedDomains, and optionally pass searchContextSize or userLocation for finer control.

typescript
import { chat } from "@tanstack/ai";
import { openRouterText } from "@tanstack/ai-openrouter";
import { webSearchTool } from "@tanstack/ai-openrouter/tools";

const stream = chat({
  adapter: openRouterText("openai/gpt-5"),
  messages: [{ role: "user", content: "What's new in AI this week?" }],
  tools: [
    webSearchTool({
      engine: "exa",
      maxResults: 5,
      allowedDomains: ["arxiv.org", "openai.com"],
    }),
  ],
});
import { chat } from "@tanstack/ai";
import { openRouterText } from "@tanstack/ai-openrouter";
import { webSearchTool } from "@tanstack/ai-openrouter/tools";

const stream = chat({
  adapter: openRouterText("openai/gpt-5"),
  messages: [{ role: "user", content: "What's new in AI this week?" }],
  tools: [
    webSearchTool({
      engine: "exa",
      maxResults: 5,
      allowedDomains: ["arxiv.org", "openai.com"],
    }),
  ],
});

Supported models: all OpenRouter chat models. See Provider Tools.

webFetchTool

Lets any OpenRouter-proxied chat model fetch the full contents of a URL the model chooses, instead of running a search. The factory accepts OpenRouter's WebFetchServerToolConfig directly — pick the fetch engine (auto — the default, native, openrouter, exa, or firecrawl), cap how much page content the model receives with maxContentTokens, cap how many fetches the model can make per request with maxUses, and restrict which URLs the model can fetch with allowedDomains / blockedDomains.

The native engine routes to the underlying provider's own fetch (for example, Anthropic's web_fetch on Claude models). Native fetch capabilities vary, so allowedDomains and blockedDomains may be ignored. Use openrouter, exa, or firecrawl if you need consistent behaviour across models.

typescript
import { chat } from "@tanstack/ai";
import { openRouterText } from "@tanstack/ai-openrouter";
import { webFetchTool } from "@tanstack/ai-openrouter/tools";

const stream = chat({
  adapter: openRouterText("openai/gpt-5"),
  messages: [
    { role: "user", content: "Summarize https://example.com/article" },
  ],
  tools: [
    webFetchTool({
      engine: "openrouter",
      maxContentTokens: 4000,
      allowedDomains: ["example.com"],
    }),
  ],
});
import { chat } from "@tanstack/ai";
import { openRouterText } from "@tanstack/ai-openrouter";
import { webFetchTool } from "@tanstack/ai-openrouter/tools";

const stream = chat({
  adapter: openRouterText("openai/gpt-5"),
  messages: [
    { role: "user", content: "Summarize https://example.com/article" },
  ],
  tools: [
    webFetchTool({
      engine: "openrouter",
      maxContentTokens: 4000,
      allowedDomains: ["example.com"],
    }),
  ],
});

Supported models: all OpenRouter chat models. See Provider Tools.

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