DeepSeek Models — cost-effective frontier AI with 1M context, open-sourced under MIT

NEW · V4.1-Flash-1017 (released 10-17)

DeepSeek-V4.1-Flash-1017 usesRLSF self-feedback reinforcement learningfor training, featuring "Wish-Driven Programming"—a single wish-style description directly produces a complete project. DeepSWE v1.1 Pass@177.0%, with an average cost per task of only about$0.20(low tier $0.10), a major improvement over the previous generation's 74.2% / $0.50. API call namedeepseek-flash: 1M context, 384K max output, native vision input, with thinking mode enabled by default.

V4.1-Flash (09-10)

MoE with 552B total parameters and native multimodality (image input), approaching or even surpassing V4-Pro (0813) on multiple benchmarks; output price reduced by about 70% versus V4-Flash, with cache-hit input as low as $0.003/million tokens.

V4 series (04-24)

V4-Pro (1.6T total parameters / 49B activated) and V4-Flash (284B / 13B) are released as open weights under the MIT license, with 1M context + 384K output, and long-context compute overhead at only 27% FLOPs / 10% KV of V3.2.

The DeepSeek V4 family brings together frontier capabilities and extremely low inference costs: V4.1-Flash-1017 uses RLSF reinforcement learning to push agentic coding costs down to about $0.20/task; V4-Pro scores 80.6% on SWE-Bench Verified and 93.5% on LiveCodeBench; all weights are open under the MIT license, with a 1M token context and 384K max output. Try it for free below — or check out the benchmark data first.

1M
token context
384K max output, handles long documents and entire codebases with ease
77.0%
DeepSWE v1.1
V4.1-Flash-1017 score, averaging about $0.20 per task
MIT
open-source license
All V4 models ship with open weights, can be self-hosted, and have no regional restrictions

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Core capabilities of the DeepSeek model family

Four capabilities define the current DeepSeek generation — officially reported scores, reproducible from MIT open weights.

Economical Million-Token Context

1M token context + 384K max output. Hybrid attention lets 1M workloads consume only about 27% of V3.2's FLOPs and 10% of the KV cache — long context no longer means a high bill.

RLSF Agentic Training

V4.1-Flash-1017 trains project development capabilities end-to-end with Reinforcement Learning from Self-Feedback (RLSF): the model uses its own confidence and self-critique as reward signals, reaching 77.0% on DeepSWE v1.1.

Native Vision Input

The V4.1-Flash series natively accepts image input with no external vision module required — screenshots, UIs, and document images go straight into the same context and tool-calling loop.

MIT Open Weights

V4-Pro and V4-Flash weights are openly available on Hugging Face under the MIT license (Flash is about 160GB), self-hostable, cleared for commercial use, with no regional restrictions, and the API is compatible with the OpenAI / Anthropic SDK.

DeepSeek Benchmark Scores: Agentic Coding and Long Context

Data sourced from DeepSeek official releases and public evaluations (as of October 2026).

EvaluationsModelsResultsDescription
DeepSWE v1.1 (Pass@1)V4.1-Flash-101777.0%Average cost per task is approximately $0.20, with the low tier at $0.10
SWE-Bench VerifiedV4-Pro80.6%Fixing real-world repository-level issues
LiveCodeBenchV4-Pro93.5%Real-time competitive programming
Terminal-Bench 2.0V4-Pro67.9%Terminal agent tasks
Codeforces (Rating)V4-Pro3,206Competitive programming Elo
Putnam-200 (Pass@8)V4-Flash81.0%Math competitions

For the 16 cross-comparisons with models such as GLM-5.3, GPT-5.6, and Claude, seeBenchmarks / DeepSeek vs GLM。

DeepSeek V4 Architecture: MoE Tiering and Hybrid Attention

Two-tier MoE + Compressed Sparse Attention keeps the compute bill for a 1M context as low as possible.

Two-Tier MoE Spec Tiers

V4-Pro has 1.6T total parameters with 49B activated per token; V4-Flash has 284B total parameters with 13B activated; V4.1-Flash at 552B features an all-new encoder design. Tiers—and their costs—switch through the same API.

Hybrid Attention

A combination of Compressed Sparse Attention (CSA) + Heavily Compressed Attention (HCA): at 1M context, FLOPs are only about 27% of V3.2's and the KV cache about 10%, optimizing long-context retrieval quality and cost at the same time.

Training and Precision

Pre-trained on 32T+ tokens with FP4+FP8 mixed precision; V4.1-Flash-1017 adds RLSF post-training: using the model's own confidence/self-critique as the reward signal, with no reliance on human evaluators.

How the 1M Context Works in Practice

1M Input · 384K Output

Entire codebases, contracts hundreds of pages long, and complete agent trajectories all fit in a single load; the 384K max output is enough to generate full projects and long reports. Thinking mode is enabled by default.

Concurrency and Ecosystem

deepseek-flash has a concurrency limit of 2500, deepseek-v4-pro 500; the API is compatible with OpenAI and Anthropic SDKs, and supports JSON output and tool calling. For details, see1M context explained。

Every DeepSeek model, version by version

The main models currently sold via API — see the full catalog atAll models。

New · Recommended

V4.1-Flash-1017

552B MoE · native vision · RLSF · 1M/384K
Call name deepseek-flash
$0.15 / $0.60 per 1M tokens (off-peak)

V4-Pro (0813)

1.6T/49B flagship · MIT · 1M/384K
API name deepseek-v4-pro
$0.66 / $1.98 per 1M tokens (off-peak)

V4.1-Flash

552B · Native vision · Released 09-10
Output price about 70% lower than V4-Flash
Cache-hit input $0.003

V4-Flash

284B/13B · MIT · ~160GB of weights
Putnam-200 81.0% · SWE-Bench 79.0%
$0.14 / $0.28 per 1M tokens

Scenarios where DeepSeek shines

Agentic coding

"Wish-Driven Programming": complete projects from a single-sentence description—official demos include a 3D model of the Forbidden City, a web-based racing game, a Godot recreation of Portal 2, and the 3D scene "Valley of Ages".

Long Documents and Whole-Repo Analysis

A 1M context window holds an entire code repository or hundreds of pages of documents; cache hits cost $0.003 per million tokens, driving the cost of RAG pipelines that repeatedly retrieve the same corpus down to nearly zero.

Self-Hosting and Enterprise Deployment

MIT open weights + OpenAI/Anthropic-compatible API: get frontier coding and reasoning capabilities without your data ever leaving the internal network, and migrating costs just one line of base_url.

FAQ

How to choose between V4-Pro and V4-Flash / V4.1-Flash?

For heavy reasoning and complex multi-file coding, choose V4-Pro; for high-concurrency, long-document, or cost-sensitive scenarios, choose deepseek-flash (now pointing to V4.1-Flash-1017, with vision support and 2500 concurrency).

Is DeepSeek free to use?

The API is pay-as-you-go with no free quota; the weights are MIT open-source, so you can deploy them yourself. The playground on this site offers free streaming demos.

Do the old model IDs still work?

Calls to v4-pro are routed to V4.1-Flash starting 2026-09-14; the official recommendation is to use deepseek-flash directly for new projects. For details, seeFAQ。

Try the real-time DeepSeek model for free — no account needed

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