DeepSeek

Access 4 DeepSeek models through Mastra's model router. Authentication is handled automatically using the DEEPSEEK_API_KEY environment variable.

Learn more in the DeepSeek documentation.

.env

DEEPSEEK_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: "deepseek/deepseek-flash"
});

// 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);
}

Models

2 available models

Model	Context	Tools	Reasoning	Image	Audio	Video	Input $/1M	Output $/1M
deepseek/deepseek-flash	1.0M						$0.15	$0.60
deepseek/deepseek-v4-pro	1.0M						$0.66	$2

Model availability, capabilities, context windows, and pricing are sourced from models.dev and may change.

Advanced configuration

Custom headers

src/mastra/agents/my-agent.ts

const agent = new Agent({
  id: "custom-agent",
  name: "custom-agent",
  model: {
    url: "https://api.deepseek.com",
    id: "deepseek/deepseek-flash",
    apiKey: process.env.DEEPSEEK_API_KEY,
    headers: {
      "X-Custom-Header": "value"
    }
  }
});

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
      ? "deepseek/deepseek-v4-pro"
      : "deepseek/deepseek-flash";
  }
});

Provider Options

DeepSeek supports the following provider-specific options via the providerOptions parameter:

const response = await agent.generate("Hello!", {
  providerOptions: {
    deepseek: {
      // See available options in the table below
    }
  }
});

Available Options

logprobs?:

boolean | undefined

Whether to return log probabilities for generated tokens.

topLogprobs?:

number | undefined

Number of most likely tokens to return at each token position. Setting this option automatically enables logprobs.

userId?:

string | undefined

An opaque identifier for the end user. DeepSeek uses this identifier for content-safety tracing and request isolation. Must contain only ASCII letters, numbers, underscores, and hyphens, and must be at most 512 characters long.

strictJsonSchema?:

boolean | undefined

Whether to use strict JSON schema validation for structured outputs. Only applies when the serving endpoint supports JSON schema response formats (e.g. Azure). Defaults to true.

thinking?:

{ type?: "enabled" | "disabled" | "adaptive" | undefined; } | undefined

reasoningEffort?:

"low" | "high" | "max" | "medium" | "xhigh" | undefined