What actually shipped on July 31 — and what didn't
It is easy to read "DeepSeek V4 official" and assume a new model dropped. It did not. The July 31 move is a post-training refresh on the same Flash skeleton. Flagship V4-Pro GA and the in-house Harness agent framework remain unreleased with no firm date.
Not a scale-up: DeepSeek states gains came entirely from post-training, not parameter growth — a 284B/13B Flash now beats a 1.6T/49B Pro preview on several agent tasks.
API-only rollout: The official build is API public beta only; consumer app and web chat were not updated.
Legacy aliases retired: deepseek-chat and deepseek-reasoner were shut down July 24 — unmigrated pipelines fail hard.
Competitive pressure: Moonshot's Kimi K3 (2.8T open weights) landed July 27, days before DeepSeek's Flash promotion.
Pro GA still vague: Chinese forums mocked "empty promise" delays before Flash surprised; V4-Pro official timing remains unconfirmed.
| Date | Event |
|---|---|
| Apr 24, 2026 | V4 preview: V4-Pro (1.6T/49B) + V4-Flash (284B/13B), 1M context, MIT weights |
| Jul 24, 2026 | Legacy model names retired; traffic routes to V4 family |
| Jul 27, 2026 | Kimi K3 2.8T weights on Hugging Face |
| Jul 31, 2026 | V4-Flash-0731 official API beta + weights; changelog names Harness "coming soon" |
| Aug 5, 2026 | V4-Pro GA still "as soon as possible"; Aug 10–20 windows are unconfirmed rumors |
DeepSeek V4-Flash pricing vs Kimi K3 and Qwen3.8-Max
| Model | Status | Total / Active | Context | Input miss/hit ($/1M) | Output ($/1M) | License |
|---|---|---|---|---|---|---|
| V4-Flash-0731 | Official Jul 31 | 284B / 13B | 1M | $0.14 / $0.0028 | $0.28 | MIT |
| V4-Pro | Preview | 1.6T / 49B | 1M | $0.435 / $0.003625 | $0.87 | MIT |
| Kimi K3 | Weights Jul 27 | 2.8T / ~104B est. | ~1.05M | $3.00 / $0.30 | $15.00 | Modified MIT |
| GLM-5.2 | Open Jun 2026 | ~744B / ~40B | 1M | Not verified here | Not verified | MIT |
| Qwen3.8-Max | API GA Aug 2 | 2.4T / 95B | 1M | $2.00 / ~$0.17–0.25 | $6.00 | Weights promised |
All figures are vendor-published list prices. DeepSeek has announced a future 2x peak-hour surcharge (9am–12pm and 2pm–6pm Beijing time) with no effective date yet. See our July 20 V4 GA breakdown for the earlier GA narrative; this article focuses on the Jul 31 Flash official build.
Vendor math vs Claude Opus 4.8: about 36x on cache-miss input, 179x on cache-hit input, 89x on output — list prices, not audited totals.
How DeepSeek squeezed more from the same model: post-training, CSA+HCA, Harness
V4-Flash-0731 is identical in size and structure to April's preview. DeepSeek attributes the agent benchmark jump entirely to a fresh post-training pass — cutting against the default "bigger equals better" assumption in 2026's model race.
Hybrid CSA+HCA attention: Compressed Sparse Attention plus Heavily Compressed Attention, marketed as DSA, cuts compute and memory at long context.
mHC hyper-connections: Manifold-Constrained Hyper-Connections refine residual paths for stability.
Muon optimizer: Replaces classic optimizers; DeepSeek claims at 1M tokens V4-Pro needs 27% of V3.2 per-token FLOPs and 10% KV cache.
July 31 also marked the first official mention of DeepSeek Harness — an in-house agent runner positioned against Claude Code. Every agent score DeepSeek published for Flash-0731 (Terminal Bench 2.0, Toolathlon, etc.) used Harness minimal mode, which is not yet public. The changelog itself warns agent scores are "extremely sensitive to harness choice."
Note: Terminal Bench 2.0 vendor score: Flash-0731 82.7 vs V4-Pro preview 67.9 — max effort, top_p 0.95, temperature 1.0, Harness minimal mode.
China's open-weight melee: Artificial Analysis index and six-step runbook
| Model | Lab | Intelligence Index | Cost per task (AA) | Note |
|---|---|---|---|---|
| V4-Flash-0731 | DeepSeek | 50 | $0.03 | Official Jul 31 |
| Kimi K3 | Moonshot | 57 | $0.86 | Higher index, ~29x cost |
| GLM-5.2 | Zhipu | ~1 pt above Flash | Not verified | Jun 2026 open |
| GPT-5.6 Sol | OpenAI | 9+ pts above | $1.86 | Closed |
| Claude Fable 5 | Anthropic | 9+ pts above | $3.15 | Closed |
Intelligence Index and per-task costs cite Artificial Analysis via financial outlets; DeepSeek's own agent scores use different harnesses — do not merge the two columns. DeepSeek is not chasing leaderboard crowns; it is optimizing for "good enough intelligence at a price nobody else matches," which also explains seven weeks atop OpenRouter usage for the preview.
Point your client: Set model to deepseek-v4-flash, keep base_url at https://api.deepseek.com; OpenAI and Anthropic SDK shapes both work.
Scrub legacy names: Search repos and CI for deepseek-chat and deepseek-reasoner.
Staging regression: Switch model names in pre-prod, compare agent pipeline quality, latency, and cache-hit rates.
Maximize prompt cache: Pin stable system prompts at the top of messages ($0.0028/M cached input).
Route by tier: Flash for bulk and routing; V4-Pro preview for heavy reasoning until official GA.
Watch Harness GA: Track changelog and Hugging Face; re-run agent benchmarks once Harness is public.
Benchmark caveats, the "kill line," and cite-ready hard data
Harness dependency: Agent headline scores are vendor plus unreleased framework — wait for Claude Code / Cursor reproductions.
Usability gaps: Overseas dev feedback cites low cache-hit rates and occasional safety-classifier timeouts — compute ceilings still matter.
"Kill line" (斩杀线): Chinese dev slang for DeepSeek's good-enough-plus-cheap combo forcing rivals to beat on capability or price — context for GPT-5.6 Luna's 80% cut.
Nvidia, Broadcom, and AMD saw muted moves on July 31 — markets now treat "DeepSeek efficiency" as routine engineering, unlike the early-2025 R1 chip selloff. Reports of a ~$7.4B funding round and IPO prep trace to unnamed financial media sources, not regulatory filings — background only.
Running V4-Flash locally via antirez ds4 needs 96GB unified memory. Pure API usage skips local hardware, but high-frequency agent pipelines still demand stable 24/7 hosts. Consumer Macs and undersized VPS instances swap-thrash under long context; short trials rarely stress 1M-token paths. For steadier iOS CI/CD and agent automation, MESHLAUNCH Mac Mini cloud rental is usually the better production bet: dedicated Apple Silicon, elastic memory tiers, and day/week/month billing.
Yes. V4-Pro and V4-Flash, including Jul 31 Flash-0731, ship as MIT weights on Hugging Face for commercial use. Cloud pricing on our rental page.
Vendor list prices: roughly 36x on cache-miss input, 179x on cache-hit input, 89x on output vs Claude Opus 4.8 per million tokens.
No confirmed date. Changelog says "as soon as possible." Aug 10–20 windows are unconfirmed rumors.
SWE-bench Verified and similar third-party suites weigh more. Terminal Bench 2.0 used unreleased Harness — treat as harness-specific until reproduced elsewhere.
DeepSeek's in-house agent runner vs Claude Code — file edits, tool calls, multi-step engineering. Named Jul 31; not yet public. See help center for cloud Mac setup.