DeepSeek V4-Pro is the open-weight value champion of 2026. A 1.6T-total / 49B-active mixture-of-experts, it posts roughly 85% on SWE-bench Verified — within a few points of the closed frontier — under a permissive MIT license and at a fraction of the price.
Its DeepSeek Sparse Attention (DSA) is what makes a 1M-token context affordable, using a small fraction of single-token FLOPs versus the previous generation at full context. The companion Flash model has since been replaced by DeepSeek V4.1-Flash, which DeepSeek reports beats V4-Pro itself on most agentic rows at $0.30 / $1.20 per million tokens at peak.
The honest caveats: it trails the absolute top on the hardest benchmarks, and some enterprise legal teams remain cautious about geopolitical and export-compliance questions despite the open license.
Update, October 2026
- GA release, August 13, 2026. The V4-Pro-0813 build rolled out on the app, web and API, with much stronger agent results — DeepSWE v1.1 62.7, Terminal-Bench 2.1 87.9, CyberGym 83.3, Toolathlon Verified 74.1 and HLE 42.7 (60.0 with tools) — plus native OpenAI Responses API support for Codex and three thinking-effort levels (low, high, max).
- New pricing, from August 16. Peak/off-peak billing replaced the flat rate: $1.32 input (cache miss) and $3.96 output per million tokens at peak, and $0.66 / $1.98 off-peak (half price). Cache-hit input is $0.044 at peak and $0.022 off-peak. Concurrency is limited to 500.
- V4.1-Flash overtakes it on most agent rows. DeepSeek first said V4-Pro requests would route to the new Flash model on September 14, then decided to keep serving V4-Pro with billing unchanged “in response to user demand”, while a V4.1-Pro is still to come.
Best for
- High-volume coding and agents on a budget
- Self-hosted deployments needing 1M context
- Cost-sensitive RAG pipelines
Pros & cons
Strengths
- Open weights (MIT) with near-frontier SWE-bench Verified (~85%)
- 1M context made cheap via DeepSeek Sparse Attention
- 5–10× lower price than the closed frontier
Limitations
- A few points behind the very top on the hardest tasks
- Some enterprise teams flag geopolitical/export-compliance uncertainty