DeepSeek

DeepSeek V4.1 Flash

A new Flash generation for coding and long-context agent work. DeepSeek's asymmetric architecture uses 8B active parameters to read input and 16B to generate output.

V4.1 generationText API accesstext inputtext output

Replaces DeepSeek V4 Flash 0731: input $0.0798 → $0.1575 per 1M (+97%), output $0.1607 → $0.63 per 1M (+292%), same context window.

Run this model

deepseek/deepseek-v4.1-flash

Use an endpoint supported by this model.

Get a key for this setup →
const response = await fetch('https://api.minirouter.sh/v1/chat/completions', {  method: 'POST',  headers: {    Authorization: `Bearer ${process.env.MINIROUTER_KEY}`,    'Content-Type': 'application/json',  },  body: JSON.stringify({    model: 'deepseek/deepseek-v4.1-flash',    messages: [{ role: 'user', content: 'Why is the sky blue?' }],  }),}) const data = await response.json()console.log(data.choices[0].message.content)
Read docs →

Use deepseek/deepseek-v4.1-flash for text requests. Image input is not supported on MiniRouter for this model. Start with the Chat Completions example; publisher client integrations do not establish MiniRouter client compatibility.

Model overview

Input / 1M
$0.1575
All-in MiniRouter rate
Output / 1M
$0.63
All-in MiniRouter rate
Context
1M
1,000,000 tokens
Max output
384K
tokens
Architecture
552B MoE
8B input / 16B output active
DeepSWE v1.1
74.2%
DeepSeek-reported, max effort
Announced
10 Sept 2026
publisher release

Publisher evidence

A step forward for coding agents.

DeepSeek reports 74.2% on DeepSWE v1.1 and 90.6% on Terminal Bench 2.1. The comparisons below come from one publisher table, with separate axes for each benchmark.

These evaluations use maximum effort (100), temperature 1.0 and top_p 0.95. Terminal Bench uses DeepSeek Harness Minimal; DeepSWE uses mini-SWE, with a 1M-token context. They are not MiniRouter performance measurements.

V4.1 vs V4

DeepSWE v1.1

Resolved repository tasks rise from 54.4% for V4 Flash and 62.7% for V4 Pro to 74.2%.

DeepSeek-reported results

0 to 100%

  • V4.1 Flash74.2%
  • V4 Pro62.7%
  • V4 Flash54.4%
DeepSeek V4.1 Flash model card, September 10, 2026. Publisher-reported at maximum reasoning effort.
View chart data
DeepSWE v1.1 values
ModelReported result
V4.1 Flash74.2%
V4 Pro62.7%
V4 Flash54.4%

V4.1 vs V4

Terminal Bench 2.1

Terminal task Pass@1 rises from 82.7% for V4 Flash and 87.9% for V4 Pro to 90.6%.

DeepSeek-reported results

0 to 100%

  • V4.1 Flash90.6%
  • V4 Pro87.9%
  • V4 Flash82.7%
DeepSeek V4.1 Flash model card, September 10, 2026. Publisher-reported at maximum reasoning effort.
View chart data
Terminal Bench 2.1 values
ModelReported result
V4.1 Flash90.6%
V4 Pro87.9%
V4 Flash82.7%

Choosing the model

Evaluate it on the work you repeat.

The strongest published improvements are in agentic coding. Task quality, tool reliability, and total tokens matter alongside the headline score.

Compare coding benchmarks
  1. 01

    Repository work and terminal tasks

    Try it on bounded fixes, code review, and tool-driven development. The published DeepSWE and Terminal Bench results make these useful starting points for your own evaluation.

  2. 02

    Long documents and repeated context

    Use the live context and output limits shown above. Repeated context may benefit from upstream caching; actual cache use and peak hours affect the final bill.

  3. 03

    Check reasoning and visual requirements

    The publisher reports GPQA Diamond at 90.9%, below V4 Pro's 92.4% in its table. The model has native vision, but MiniRouter currently supports text input for this route.

Live route pricing

Plan around peak hours and output tokens.

The price panel uses MiniRouter's catalog rates, including the 5% markup. DeepSeek's provider route charges 2× from 01:00–04:00 and 06:00–10:00 UTC, Monday–Friday; all other hours are off-peak.

Publisher pricing and schedule
  1. 01

    Separate list prices from your route price

    DeepSeek lists $0.15/M uncached input and $0.60/M output off-peak, before MiniRouter's markup. Peak list prices are $0.30/M and $1.20/M respectively.

  2. 02

    Compare the whole task

    Reasoning and longer answers can increase output usage. Compare total task cost and success rate with V4 Flash or another coding model using the same tools and prompt.

From V4 and the beta

Use the permanent model ID.

The September 10 release is distinct from the temporary V4.1 Flash beta. Select the exact model ID in your API request and rerun your representative tasks.

Read the release and API changes
  1. 01

    Replace the beta ID

    Change deepseek/deepseek-v4.1-flash-beta to deepseek/deepseek-v4.1-flash once the permanent model appears in MiniRouter's catalog. Keep your MiniRouter base URL and key.

  2. 02

    Check aliases at the provider boundary

    DeepSeek's direct API uses deepseek-flash and redirects older V4 aliases. Those publisher redirects do not guarantee that a MiniRouter V4 ID selects this release.

  3. 03

    Keep evaluation results separate

    The September 10 Artificial Analysis API refresh has no matching V4.1 Flash evaluation. Use the publisher results above as evidence to investigate; independent speed and quality measurements are not yet included here.

One route, standard clients.

Authenticate with a MiniRouter bearer key. Caller-provided upstream credentials are not used on this route.

Read model setup docs →
Base URLhttps://api.minirouter.sh/v1
Model IDdeepseek/deepseek-v4.1-flash
Endpoints
/v1/chat/completions/v1/messages/v1/responses
Parameters

max_tokens, temperature, stop, tools, tool_choice, reasoning, include_reasoning

Configured provider

Priority follows the live catalog order.

Input: text · Output: text

ProviderPriorityInput / 1MOutput / 1MParametersAccess
vercel
1$0.1575$0.63max_tokens, temperature, stop, tools, tool_choice, reasoning, include_reasoningMiniRouter balance