How to Use the DeepSeek V4.1 Flash API

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

DeepSeek V4.1 Flash is available on EmpirioLabs. It is the lightweight flagship of DeepSeek's new architecture family: a 552B-parameter mixture-of-experts model with 8B active parameters for input and 16B for output, native image understanding, a 1M token context window, and up to 384K output tokens. DeepSeek reports benchmark results ahead of DeepSeek V4 Pro.

What the model does

V4.1 Flash reads text and images in the same request, so you can send screenshots, diagrams, and photos alongside a prompt. Hybrid thinking is on by default: the model reasons before it answers, and you can turn thinking off for lower-latency replies or cap it with a thinking budget. Function calling and JSON mode work on the standard chat completions surface, and optional Linkup web search adds recent web context when you enable it.

How to call DeepSeek V4.1 Flash

Use the OpenAI-compatible chat completions endpoint and set model to deepseek-v4-1-flash. Image parts use the standard image_url content block:

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",
    "enable_thinking": true,
    "thinking_budget": 32768,
    "messages": [
      {
        "role": "user",
        "content": [
          {"type": "text", "text": "What does this chart show? Summarize the trend in two sentences."},
          {"type": "image_url", "image_url": {"url": "https://example.com/chart.png"}}
        ]
      }
    ]
  }'

The same model id works on the Responses, Messages, and Gemini-compatible endpoints listed on the model page.

Operational notes

• JSON mode (a response_format of type json_object) requires the word json somewhere in your messages. The strict JSON Schema response format is not available on this model.
• Reasoning tokens are billed as output tokens. Set enable_thinking to false for short, latency-sensitive replies, or lower thinking_budget to bound the reasoning.

Pricing

Token usage is billed at one published input rate and one published output rate, with no separate cached-input rate. 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 in the Playground, read the API documentation, or compare it with other models in the model catalog.