DeepSeek-V3.1 is a large hybrid reasoning model (671B parameters, 37B active) that supports both thinking and non-thinking modes via prompt templates. It extends the DeepSeek-V3 base with a two-phase long-context training process, reaching up to 128K tokens, and uses FP8 microscaling for efficient inference. Users can control the reasoning behaviour with the `reasoning` `enabled` boolean. It supports structured tool calling, code agents, and search agents, making it suitable for research, coding, and agentic workflows. It succeeds the [DeepSeek V3-0324](/deepseek/deepseek-chat-v3-0324) model and performs well on a variety of tasks.

Pricing

Price per input token: $0

Price per output token: $0

Usage Example

NOTE: BrainLink is compatible with the OpenAI API, which allows you to use the OpenAI SDK even with non-OpenAI models

import OpenAI from "openai";
const userAccessToken = await BrainLink.getUserToken();
const openai = new OpenAI({
    baseURL: "https://www.brainlink.dev/api/v1",
    apiKey: userAccessToken,
});
const completion = await openai.chat.completions.create({
    model: "deepseek/deepseek-chat-v3.1:free",
    messages: [
      { role: "user", content: "Hi! How are you today?" }
    ],
});