DeepSeek V4.1 Flash

4.95
DeepSeek V4.1 Flash has taken over from Pro with a larger model, a 1-million-token context window, built-in vision, and lower API pricing. Some published scores already beat V4 Pro. What matters now is how that holds up in real workloads.
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CompanyDeepSeek
Context1M
Released2026-09
Updated2026-09-10

DeepSeek V4.1 Flash Overview

DeepSeek V4.1 Flash is a 552B-parameter Mixture-of-Experts (MoE) model built on a Causal-Encoder-Decoder architecture.

It activates roughly:

8B parameters while processing input
16B parameters while generating output

The context window is 1 million tokens, with a maximum output length of 384K tokens.

It accepts text, images, screenshots, and charts. The API supports JSON output, tool calling, the Responses API, and three reasoning settings: low, high, and max.

The same model can handle long documents, code repositories, agents, knowledge bases, and mixed text-and-image workloads.

DeepSeek V4.1 Flash Pricing

PlanPriceDescription
API input — cache hit CNY 0.02 / 1M tokens off-peak; CNY 0.04 / 1M at peak Useful when reusing the same context
API input — cache miss CNY 1 / 1M tokens off-peak; CNY 2 / 1M at peak Charged by input tokens
API output CNY 4 / 1M tokens off-peak; CNY 8 / 1M at peak Charged by generated tokens
Web / App Free Chat, writing, research, and everyday use

Peak rates apply on weekdays from 9:00 a.m.–12:00 p.m. and 2:00–6:00 p.m. Other hours use off-peak pricing.

Compared with V4 Flash:

  • Cache-hit input is 60% cheaper
  • Uncached input is 33% cheaper
  • Output is 11% cheaper

DeepSeek V4.1 Flash Key Features

1. Vision Is Built Into the Main Model

V4 Flash Vision Exp needed an extra vision component.

V4.1 Flash handles text, screenshots, images, and charts in the main model.

A reporting workflow can read a screenshot, interpret a chart, organize the data, and continue with tool calls without switching models.

That makes the stack simpler.

Dense dashboards, tiny text, and complicated charts still need separate testing. Visual tasks vary too much to judge from the feature list alone.

2. The 1M Context Window Is Faster

The context limit remains 1 million tokens.

In DeepSeek's published 49K long-context retrieval test, V4.1 Flash ran 5.2× faster than V4 Flash Vision Exp. SVG code generation was about 6× faster.

That speed is most useful with large documents and code repositories.

A 300K- or 500K-token repository may fit comfortably in context, but processing time still affects the experience. For agents that repeat the cycle over many steps, the delay can build up fast.

3. Reading Uses Less Active Compute

V4.1 Flash activates about 8B parameters while processing input and 16B during generation.

Code analysis, RAG, and enterprise search often involve much more input than output.

A large repository may contain hundreds of thousands of tokens, while the final review is only a few thousand. A knowledge-base request may pull in pages of source material and return a short answer.

At scale, input processing becomes a significant part of the bill.

V4.1 Flash uses less active compute on the input side, and DeepSeek has also cut input pricing.

4. What Changed From V4 Flash?

The main changes are:

  • Model size increased to 552B parameters
  • Causal-Encoder-Decoder architecture
  • Vision moved into the main model
  • Faster long-context processing
  • Lower API input and output prices

Published scores include:

  • GPQA Diamond: 90.9
  • Codeforces: 3471
  • Terminal-Bench 2.1: 90.6

Some of those results are higher than V4 Pro's published scores.

The “Flash” name usually suggests lower cost with some performance trade-offs. So far, V4.1 Flash does not look heavily cut down.

We have not run that side-by-side test ourselves yet.

The clean comparison would be the same repository, same prompt, and same tools on both models, repeated several times. Runtime, cost, errors, and tool-call failures would tell us much more than a single benchmark score.

Summary

Strengths

  • Low API pricing
  • 1-million-token context window
  • Faster long-context processing
  • Vision built into the main model
  • Some published scores beat V4 Pro

Limitations

  • Limited production-scale data
  • Very long contexts can still use a lot of tokens
  • Complex vision tasks need separate testing
  • Peak and off-peak API rates differ

Best For

  • Developers building agents, RAG systems, and enterprise knowledge bases
  • Teams working with large code repositories
  • Businesses processing long documents at scale
  • High-volume API workloads
  • Products that need both text and visual input

Probably Not Worth It For

  • Casual chat and everyday writing
  • Developers making very few API calls
  • Lightweight apps that do not need long context
  • Workloads where maximum performance matters more than cost

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