# Use BigModel.io with the Vercel AI SDK

> Use BigModel.io from the Vercel AI SDK with @ai-sdk/openai-compatible or @ai-sdk/anthropic. Both take https://bigmodel.io/v1 as baseURL. generateText, streamText and tools.

Web version: https://bigmodel.io/docs/vercel-ai-sdk · Updated 2026-10-18

The Vercel AI SDK reaches BigModel.io through two providers. `@ai-sdk/openai-compatible` works with any key; `@ai-sdk/anthropic` needs a key whose group serves `/v1/messages`.

| Provider | `baseURL` | Endpoint called |
|---|---|---|
| `@ai-sdk/openai-compatible` | `https://bigmodel.io/v1` | `/v1/chat/completions` |
| `@ai-sdk/anthropic` | `https://bigmodel.io/v1` | `/v1/messages` |

> Unlike the Anthropic SDK, `@ai-sdk/anthropic`'s default `baseURL` already includes `/v1`, so use `https://bigmodel.io/v1` here, not the root.

Copy model IDs from the [model catalog](https://bigmodel.io/models); availability depends on the key's group. Run this code on the server (route handler, server action, script), never in the browser, so the key stays private.

```bash
export BIGMODEL_API_KEY="sk-..."
```

## Install

```bash
npm install ai @ai-sdk/openai-compatible @ai-sdk/anthropic zod
```

## OpenAI-compatible provider

```ts [TypeScript]
import { createOpenAICompatible } from "@ai-sdk/openai-compatible";
import { generateText } from "ai";

const bigmodel = createOpenAICompatible({
  name: "bigmodel",
  baseURL: "https://bigmodel.io/v1",
  apiKey: process.env.BIGMODEL_API_KEY,
  includeUsage: true,
});

const { text, usage } = await generateText({
  model: bigmodel("glm-5.3"),
  prompt: "Explain vector databases in three sentences.",
});
console.log(text, usage);
```

`includeUsage: true` asks for token usage on streamed responses as well. If you rely on JSON schema output, check [Structured output](https://bigmodel.io/docs/structured-output) before setting `supportsStructuredOutputs`.

## Anthropic provider

```ts [TypeScript]
import { createAnthropic } from "@ai-sdk/anthropic";
import { generateText } from "ai";

const bigmodelAnthropic = createAnthropic({
  baseURL: "https://bigmodel.io/v1",
  apiKey: process.env.BIGMODEL_API_KEY, // sent as x-api-key; use authToken for Bearer
});

const { text } = await generateText({
  model: bigmodelAnthropic("glm-5.3"),
  prompt: "Explain vector databases in three sentences.",
});
console.log(text);
```

## Streaming

```ts [TypeScript]
import { streamText } from "ai";

const result = streamText({
  model: bigmodel("glm-5.3"),
  prompt: "Write a haiku about latency.",
});
for await (const delta of result.textStream) {
  process.stdout.write(delta);
}
```

In a Next.js route handler, return `result.toTextStreamResponse()` instead of looping.

## Tool calling

Tools are sent in the provider's native format and forwarded to the model. Whether a model calls them depends on the model.

```ts [TypeScript]
import { generateText, tool } from "ai";
import { z } from "zod";

const result = await generateText({
  model: bigmodel("glm-5.3"),
  prompt: "What's the weather in Hangzhou?",
  tools: {
    getWeather: tool({
      description: "Get the current weather for a city",
      inputSchema: z.object({ city: z.string() }),
      execute: async ({ city }) => `Sunny in ${city}`,
    }),
  },
});
console.log(result.toolCalls, result.toolResults);
```

`inputSchema` is the AI SDK 5 name; older 4.x releases call it `parameters`.

## Verify the setup

Run the `generateText` example. A reply with a non-zero `usage` means the base URL and key work. The request should appear in [Usage](https://bigmodel.io/usage) with endpoint `/v1/chat/completions` (or `/v1/messages` for the Anthropic provider).

## Troubleshooting

**404 with `@ai-sdk/anthropic`.** Either `baseURL` is the root (`https://bigmodel.io`), so the SDK calls `/messages`, or the key's group is Chat Completions only (`... platform only supports /v1/chat/completions`). Use `https://bigmodel.io/v1`, or switch to `@ai-sdk/openai-compatible`.

**404 with `@ai-sdk/openai-compatible`.** `baseURL` is missing `/v1`.

**401 `INVALID_API_KEY` or `API_KEY_REQUIRED`.** `BIGMODEL_API_KEY` is not set in the server runtime (check your hosting provider's environment variables).

**503 `No available accounts: no available accounts supporting model: ...`.** The model ID is wrong or not in the key's group. Copy it from the [model catalog](https://bigmodel.io/models).

**`usage` is empty when streaming.** Set `includeUsage: true` on `createOpenAICompatible`.

**403 `INSUFFICIENT_BALANCE` or 429.** Top up in [Billing](https://bigmodel.io/purchase); for 429 see [Limits & rate limits](https://bigmodel.io/docs/rate-limits).

## Related

- [OpenAI SDK](https://bigmodel.io/docs/openai-sdk-langchain) and [Anthropic SDK](https://bigmodel.io/docs/anthropic-sdk)
- [OpenCode](https://bigmodel.io/docs/opencode) uses `@ai-sdk/openai-compatible` under the hood
- [Streaming](https://bigmodel.io/docs/streaming) and [Tool calling](https://bigmodel.io/docs/tool-calling)