Inference
Access 9 Inference models through Mastra’s model router. Authentication is handled automatically using the INFERENCE_API_KEY environment variable.
Learn more in the Inference documentation .
INFERENCE_API_KEY=your-api-keyimport { Agent } from "@mastra/core";
const agent = new Agent({
name: "my-agent",
instructions: "You are a helpful assistant",
model: "inference/google/gemma-3"
});
// 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);
}Mastra uses the OpenAI-compatible /chat/completions endpoint. Some provider-specific features may not be available. Check the Inference documentation for details.
Models
| Model | Context | Tools | Reasoning | Image | Audio | Video | Input $/1M | Output $/1M |
|---|---|---|---|---|---|---|---|---|
inference/mistral/mistral-nemo-12b-instruct | 16K | $0.04 | $0.10 | |||||
inference/google/gemma-3 | 125K | $0.15 | $0.30 | |||||
inference/osmosis/osmosis-structure-0.6b | 4K | $0.10 | $0.50 | |||||
inference/qwen/qwen3-embedding-4b | 32K | $0.01 | — | |||||
inference/qwen/qwen-2.5-7b-vision-instruct | 125K | $0.20 | $0.20 | |||||
inference/meta/llama-3.2-11b-vision-instruct | 16K | $0.06 | $0.06 | |||||
inference/meta/llama-3.1-8b-instruct | 16K | $0.03 | $0.03 | |||||
inference/meta/llama-3.2-3b-instruct | 16K | $0.02 | $0.02 | |||||
inference/meta/llama-3.2-1b-instruct | 16K | $0.01 | $0.01 |
Advanced Configuration
Custom Headers
const agent = new Agent({
name: "custom-agent",
model: {
url: "https://inference.net/v1/chat/completions",
modelId: "google/gemma-3",
apiKey: process.env.INFERENCE_API_KEY,
headers: {
"X-Custom-Header": "value"
}
}
});Dynamic Model Selection
const agent = new Agent({
name: "dynamic-agent",
model: ({ runtimeContext }) => {
const useAdvanced = runtimeContext.task === "complex";
return useAdvanced
? "inference/google/gemma-3"
: "inference/meta/llama-3.1-8b-instruct";
}
});