How do I use DeepSeek V4.1 Flash through YepAPI?

Sign up for a free API key, then send requests to the /v1/ai/chat endpoint.

DeepSeekText Generation/v1/ai/chat

DeepSeek V4.1 Flash

Access DeepSeek V4.1 Flash through one API key. DeepSeek Ultra-Cheap Sparse MoE.

DeepSeek V4.1 Flash is a sparse mixture-of-experts model from DeepSeek, and the first built on the company's Causal Encoder-Decoder architecture. V4.1 Flash is the model for very high-volume work — extraction, summarisation, classification, drafting — where the per-call price has to be close to zero.

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2,400+

Developers

1.2M+

API calls served

100+

Endpoints

$0.01

Per call

Yep, that's it.

Try it live

Send a message and see DeepSeek V4.1 Flash respond in real time.

POST/v1/ai/chatdeepseek/deepseek-v4.1-flash

Message *

Max Tokens

Maximum tokens in the response.

Stream

Real-time tokens

Hit "Send Request" to see the response

Context Window

1.0M tokens

Max Output

384K tokens

Input Price

$0.05 / 1M tokens

Output Price

$0.43 / 1M tokens

Strengths

✓

Near-zero cost

$0.05 per 1M input and $0.43 per 1M output tokens.

✓

New CED architecture

DeepSeek's first Causal Encoder-Decoder model, activating 8B parameters on input and 16B on output.

✓

1M context, 384K output

Handles up to 1,048,576 input tokens and returns up to 384,000 output tokens per call.

✓

Image input

Accepts text and images.

Quick start

Copy this snippet and start making calls with DeepSeek V4.1 Flash.

const res = await fetch('https://api.yepapi.com/v1/ai/chat', {
  method: 'POST',
  headers: {
    'x-api-key': 'YOUR_API_KEY',
    'Content-Type': 'application/json',
  },
  body: JSON.stringify({
    "model": "deepseek/deepseek-v4.1-flash",
    "messages": [
      {
        "role": "user",
        "content": "Explain API gateways in 2 sentences."
      }
    ],
    "maxTokens": 256
  }),
});
const { data } = await res.json();
console.log(data.message.content);

Why use DeepSeek V4.1 Flash through YepAPI?

✓One API key for all models — no separate accounts

✓OpenAI SDK compatible — just change the base URL

✓No monthly minimums — pay per token

✓Switch models with one line of code

✓Full provider passthrough — citations, search results, and all extras included

✓Streaming and non-streaming support on every model

✓Works with Cursor, Claude, LangChain, and any LLM tool

✓Unified billing across all providers

DeepSeek V4.1 Flash API — pricing, context window & access

DeepSeek V4.1 Flash is a sparse mixture-of-experts model from DeepSeek, and the first built on the company's Causal Encoder-Decoder architecture. It pairs a 1,048,576-token context window with up to 384,000 output tokens per response, at $0.05 per 1M input and $0.43 per 1M output tokens through YepAPI.

Through YepAPI you call DeepSeek V4.1 Flash on an OpenAI-compatible endpoint with a single key — the same key that reaches GPT-6, Claude, Gemini, Grok and the SEO, SERP and scraping APIs. Input: text, images.

What is DeepSeek V4.1 Flash?

DeepSeek V4.1 Flash is a sparse mixture-of-experts model from DeepSeek, and the first built on the company's Causal Encoder-Decoder architecture. It activates 8B parameters on input and 16B on output, which is how it reaches $0.05 / $0.43 per 1M tokens while keeping a 1,048,576-token context window, up to 384,000 output tokens, and image input. It accepts text, images as input, handles up to 1,048,576 tokens of context and returns up to 384,000 output tokens per call.

Build with DeepSeek V4.1 Flash via YepAPI

YepAPI serves DeepSeek V4.1 Flash on the OpenAI-compatible /v1/ai/chat endpoint. Point your base URL at YepAPI, add your key, and set the model string to deepseek-v4.1-flash (or the full deepseek/deepseek-v4.1-flash). Function calling, structured outputs and reasoning settings pass straight through, and switching to any other model on the platform is a one-string change per request.

DeepSeek V4.1 Flash API pricing — $0.05 / 1M input, $0.43 / 1M output

DeepSeek V4.1 Flash costs $0.05 per 1M input tokens and $0.43 per 1M output tokens through YepAPI, pay per token with no minimums. Failed calls are never charged, and every request is itemised in your dashboard API Logs so you can see exactly what a very long response cost.

DeepSeek V4.1 Flash use cases

V4.1 Flash is the model for very high-volume work — extraction, summarisation, classification, drafting — where the per-call price has to be close to zero.

Try DeepSeek V4.1 Flash free

Every new YepAPI account includes $5 in free credit with no card required — enough to test DeepSeek V4.1 Flash on your own prompts before committing to paid usage. Create an account, copy your key, and call deepseek-v4.1-flash right away.