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Access 47 FastRouter models through Mastra's model router. Authentication is handled automatically using the FASTROUTER_API_KEY environment variable.

Learn more in the FastRouter documentation.

.env
FASTROUTER_API_KEY=your-api-key
src/mastra/agents/my-agent.ts
import { Agent } from "@mastra/core/agent";

const agent = new Agent({
  id: "my-agent",
  name: "My Agent",
  instructions: "You are a helpful assistant",
  model: "fastrouter/anthropic/claude-opus-4.1"
});

// Generate a response
const response = await agent.generate("Hello!");

// Stream a response
const stream = await agent.stream("Tell me a story");
for await (const chunk of stream) {
  console.log(chunk);
}
info

Mastra uses the OpenAI-compatible /chat/completions endpoint. Some provider-specific features may not be available. Check the FastRouter documentation for details.

Models
Direct link to Models

ModelContextToolsReasoningImageAudioVideoInput $/1MOutput $/1M
fastrouter/anthropic/claude-opus-4.1200K$15$75
fastrouter/anthropic/claude-opus-4.81.0M$5$25
fastrouter/anthropic/claude-sonnet-4200K$3$15
fastrouter/anthropic/claude-sonnet-4.61.0M$3$15
fastrouter/bytedance/seedance-24K——
fastrouter/deepseek-ai/deepseek-r1-distill-llama-70b131K$0.03$0.14
fastrouter/deepseek/deepseek-v4-pro1.0M$2$3
fastrouter/google/gemini-2.5-flash1.0M$0.30$3
fastrouter/google/gemini-2.5-pro1.0M$1$10
fastrouter/google/gemini-3-pro-image-preview66K$2$12
fastrouter/google/gemini-3.1-flash-image-preview66K$0.50$3
fastrouter/google/gemini-3.1-pro-preview1.0M$2$12
fastrouter/google/gemini-3.5-flash1.0M$2$9
fastrouter/google/gemma-4-31b-it262K$0.13$0.38
fastrouter/google/imagen-4.0-fast480——
fastrouter/google/imagen-4.0-ultra480——
fastrouter/google/veo3.1400K——
fastrouter/google/veo3.1-fast400K——
fastrouter/google/veo3.1-lite400K——
fastrouter/leonardo-ai/lucid-origin4K——
fastrouter/leonardo-ai/lucid-realism4K——
fastrouter/minimax/minimax-m2.7205K$0.30$1
fastrouter/minimax/minimax-m2.7-highspeed205K$0.60$2
fastrouter/moonshotai/kimi-k2131K$0.55$2
fastrouter/moonshotai/kimi-k2.6262K$0.75$4
fastrouter/openai/gpt-4.11.0M$2$8
fastrouter/openai/gpt-5400K$1$10
fastrouter/openai/gpt-5-mini400K$0.25$2
fastrouter/openai/gpt-5-nano400K$0.05$0.40
fastrouter/openai/gpt-5.3-codex400K$2$14
fastrouter/openai/gpt-5.4-mini400K$0.75$5
fastrouter/openai/gpt-5.4-nano400K$0.20$1
fastrouter/openai/gpt-5.51.1M$5$30
fastrouter/openai/gpt-5.5-pro1.1M$30$180
fastrouter/openai/gpt-image-2128K——
fastrouter/openai/gpt-oss-120b131K$0.15$0.60
fastrouter/openai/gpt-oss-20b131K$0.05$0.20
fastrouter/openai/gpt-realtime-1.532K$4$16
fastrouter/qwen/qwen3-coder262K$0.30$1
fastrouter/sarvam/sarvam-105b131K$0.04$0.16
fastrouter/sarvam/sarvam-30b128K$0.02$0.10
fastrouter/wanx/wan-v2-6400K——
fastrouter/x-ai/grok-4256K$3$15
fastrouter/x-ai/grok-4.31.0M$1$3
fastrouter/x-ai/grok-build-0.1256K$1$2
fastrouter/z-ai/glm-5205K$0.95$3
fastrouter/z-ai/glm-5.1200K$1$4
47 available models

Advanced configuration
Direct link to Advanced configuration

Custom headers
Direct link to Custom headers

src/mastra/agents/my-agent.ts
const agent = new Agent({
  id: "custom-agent",
  name: "custom-agent",
  model: {
    url: "https://go.fastrouter.ai/api/v1",
    id: "fastrouter/anthropic/claude-opus-4.1",
    apiKey: process.env.FASTROUTER_API_KEY,
    headers: {
      "X-Custom-Header": "value"
    }
  }
});

Dynamic model selection
Direct link to Dynamic model selection

src/mastra/agents/my-agent.ts
const agent = new Agent({
  id: "dynamic-agent",
  name: "Dynamic Agent",
  model: ({ requestContext }) => {
    const useAdvanced = requestContext.task === "complex";
    return useAdvanced
      ? "fastrouter/z-ai/glm-5.1"
      : "fastrouter/anthropic/claude-opus-4.1";
  }
});
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