Use Router One with the AI SDK's Chat Completions API
Use the Vercel AI SDK's OpenAI provider with Router One to call supported models through one base URL and key. Select the API explicitly: this guide uses Chat Completions with router.chat(modelId), including with generateText and streamText. Check model capabilities before adding tools or structured output; each gateway model request has its own cost trace.
Configure Vercel AI SDK to use the Router One base URL
Create the provider with createOpenAI and the Router One base URL, then pass a compatible catalog ID to router.chat(). Since AI SDK 5, router(modelId) defaults to the Responses API; router.chat(modelId) explicitly selects /v1/chat/completions. Use router.responses(modelId) only for a model and feature set supported on /v1/responses:
import { createOpenAI } from "@ai-sdk/openai";
import { generateText } from "ai";
const router = createOpenAI({
baseURL: "https://api.router.one/v1",
apiKey: "sk-your-router-one-key",
});
const { text } = await generateText({
model: router.chat("<model-id-from-/models>"),
prompt: "Hello!",
});Which model ID should Vercel AI SDK send?
Copy the exact model ID from /models, preserving case, hyphens, and version suffixes; do not substitute a display name. Open its detail page and match the supported API endpoints, context window, and capabilities such as tool calling to the provider and features selected in Vercel AI SDK. A catalog listing does not mean the client can use every feature of that model. Give each tool a dedicated API key with a maxSpend cap.
Which API protocol is Vercel AI SDK using?
OpenAI-compatible describes an interface format; it does not make Chat Completions (/v1/chat/completions), Responses (/v1/responses), and Anthropic Messages (/v1/messages) interchangeable. Check the installed client version, provider configuration, and actual request path against the model detail page and API compatibility fact sheet. A successful plain-text chat does not establish support for hosted tools, conversation state, or file-editing features.
Verify the Vercel AI SDK call in your request trace
Send a simple text request from Vercel AI SDK, then match its trace in Dashboard → Logs by time, model, and request_id: tokens, cost, latency, and status. Next, test streaming, tool calls, and multi-turn history separately. For failures, retain the actual request path, full error message, and request_id. If there is no matching log, check client configuration and connectivity before attributing the error to the gateway or upstream.
FAQ
Does streaming work through the gateway?
Use streamText with router.chat(modelId) for streaming Chat Completions and a model that supports it. Responses uses a different event format; a successful Chat Completions stream does not verify Responses tools or conversation state. Verify the final request status and usage in Dashboard → Logs.
Which models can Vercel AI SDK use through the gateway?
Choose a current catalog model that supports both the endpoint and the features Vercel AI SDK uses. Check /models and the model detail page for the exact ID, current rates, and capabilities; a family name such as GPT or Claude is not a compatibility guarantee. Seeing a model in the picker confirms discovery, so verify an actual request too.
Models are listed, but requests fail with 400 or 404. What should I check?
Record the actual request path and error message, then check the exact model ID. A 400 can indicate invalid parameters, unsupported tools, or a model/endpoint mismatch; a 404 can indicate an incorrect path or missing resource, so it does not by itself establish that a model was retired. If the error says must be called via, use the named endpoint or select a model supported on the current endpoint. Do not add or remove /v1 or /chat/completions across all clients indiscriminately.
Does this work from Mainland China?
Yes. The gateway is reachable from Mainland China without a VPN, and the configuration is identical to the global setup.
How do I debug a 401/402/403/429?
Match the request and error message in Dashboard → Logs. For 401, check whether the key was sent and is valid; for 402, check wallet balance and maxSpend; for 403, check key permissions and access restrictions. For 429, distinguish request/token limits from upstream throttling using the error details. Keep the request_id and follow the error-codes reference.