How to Use the DeepSeek V4.1 Flash 1017 API

Disclosure: This article was written with AI assistance and reviewed by EmpirioLabs AI.

DeepSeek V4.1 Flash 1017 is available on EmpirioLabs. It is DeepSeek's October 17 update to DeepSeek V4.1 Flash. DeepSeek reports stronger coding and agent results, faster task completion, and shorter answers than the September release. The model keeps V4.1 Flash's image input, hybrid thinking, function calling, and 1M token context window, with up to 384K output tokens.

Watch the launch film

Every program in the film was written by DeepSeek V4.1 Flash 1017 in one shot and is shown running as written. The score was generated by ACE-Step on EmpirioLabs. Watch it on YouTube.

What the model does

Text and image input. Send screenshots, diagrams, and photos in the same request as the prompt, using the standard image_url content block.

Hybrid thinking. Thinking is on by default, so the model reasons before it answers. Set enable_thinking to false for lower-latency replies, or cap the reasoning with thinking_budget.

Tools and structured output. Function calling and JSON mode work on the chat completions endpoint. Optional Linkup web search adds recent web results to the context when you set web_search_linkup to true.

How to call DeepSeek V4.1 Flash 1017

Use the OpenAI-compatible chat completions endpoint and set model to deepseek-v4-1-flash-1017. This request gives the model a tool and lets it decide when to call it:

curl https://api.empiriolabs.ai/v1/chat/completions \
  -H "Authorization: Bearer $EMPIRIOLABS_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "deepseek-v4-1-flash-1017",
    "enable_thinking": true,
    "thinking_budget": 8192,
    "messages": [
      {"role": "user", "content": "The test test_parse_dates fails after the last commit. Read src/dates.py and tell me what to check first."}
    ],
    "tools": [
      {
        "type": "function",
        "function": {
          "name": "read_file",
          "description": "Read a file from the repository",
          "parameters": {
            "type": "object",
            "properties": {"path": {"type": "string"}},
            "required": ["path"]
          }
        }
      }
    ]
  }'

The response contains a read_file tool call with the path as its argument. Run the tool, add its result as a tool message, and send the conversation back for the next step. The same model ID works on the Responses, Messages, and Gemini-compatible endpoints listed on the model page.

1017 or V4.1 Flash?

Dated model ID. deepseek-v4-1-flash-1017 always serves the October 17 release, so evaluations and production prompts keep the same model until you change the ID.

Earlier model ID. deepseek-v4-1-flash retires on October 27, 2026. From that date it keeps working and is served by deepseek-v4-1-flash-1017, so code that still sends it needs no change.

Operational notes

• JSON mode needs the word json in the messages. A response_format of type json_object is rejected unless the word json appears in the prompt. Strict JSON Schema output (json_schema) is not available on this model.
• Linkup answers end with a Sources list. Set disable_formatting to true when another program reads the output and expects the answer alone.

Pricing

Token usage is billed at one published input rate and one published output rate, with no separate cached-input rate. Reasoning tokens are billed as output tokens. Linkup web search adds a small per-call fee only when it runs. See the live model page and pricing page for current rates.

Start building

Try DeepSeek V4.1 Flash 1017 in the Playground, read the API documentation, or compare it with other models in the model catalog.