DeepSeek

Key Terms

• Peak / off-peak pricing - time-of-day pricing where peak rates are exactly 2x off-peak. Peak hours are 01:00-04:00 and 06:00-10:00 UTC, Monday through Friday, excluding Chinese public holidays; all other hours including full weekends and Chinese holidays are off-peak. Source: DeepSeek – Pricing
• Causal Encoder-Decoder (CED) - V4.1-Flash's architecture: a 40-layer Transformer split into a 20-layer causal encoder and a 20-layer decoder, where the decoder's global KV cache is projected from the final encoder hidden states. This activates only 8B parameters per token during prefill and 16B during decode. Source: Hugging Face – Deepseek V4.1 Flash
• CSA2 (Compressed Sparse Attention 2) - V4.1-Flash's attention scheme that assigns each layer one of three static modes (Full, Reindex, Reuse) and uses FP4 main KV caching, compressing the KV cache to 890 bytes per token, roughly 1/4 of V4-Flash. Source: Hugging Face – Deepseek V4.1 Flash
• Engram conditional memory - a 196B-parameter sparsely-accessed memory component in V4.1-Flash, looked up by token, separate from the 552B backbone. Source: Hugging Face – Deepseek V4.1 Flash
• DeepSeek Harness (dsh) - DeepSeek's first-party agent harness, in developer preview: a Web UI plus Python SDK that can read/edit workspace files, run commands, delegate work, and keep a plan, with GitHub review automation and MCP memory integrations. Source: Deepseek-Harness – Quickstart
• Model alias routing - retired model names still resolve: deepseek-v4-flash and deepseek-v4-flash-vision-exp are accepted but served by V4.1-Flash and billed at Flash prices. Source: DeepSeek – Pricing
• Concurrency limit - simultaneous in-flight requests per account (2,500 Flash, 500 Pro); exceeding it returns HTTP 429. Free capacity expansion is available on request. Source: DeepSeek – Rate Limit
• user_id isolation - a per-end-user parameter that isolates content safety handling, KV cache, and scheduling under one account; with expanded quotas, each user_id gets its own concurrency cap (2,500 Flash / 500 Pro). Source: DeepSeek – Rate Limit

Latest Changes

Changes since the 2026-08 report.

• New model: DeepSeek-V4.1-Flash launched 2026-09-10, a 552B-backbone multimodal MoE (763B total checkpoint including the 196B Engram memory), 1M context, 384K max output, native vision, continuously controllable reasoning effort 1-100, MIT-licensed weights on Hugging Face. Source: DeepSeek – News260910 ; Hugging Face – Deepseek V4.1 Flash
• Models retired: V4-Flash-0731 and V4-Flash-Vision-Exp (the August lineup's other two models) are retired; the names deepseek-v4-flash and deepseek-v4-flash-vision-exp temporarily route to V4.1-Flash at Flash prices. Source: DeepSeek – Pricing
• Policy reversal (V4-Pro): the Sept 10 news post said all deepseek-v4-pro requests would route to V4.1-Flash at Flash rates from 04:00 UTC Sept 14 "until V4.1-Pro launches"; the same-day change log reversed this "in response to user demand," continuing V4-Pro service with unchanged billing. Source: DeepSeek – News260910 ; DeepSeek – Updates
• Price cut (Flash): off-peak Flash dropped from August's $0.22/$0.66 to $0.15/$0.60 per MTok (cache-miss input/output), a 32% input cut and 9% output cut; peak is 2x ($0.30/$1.20). Pro pricing is unchanged ($0.66/$1.98 off-peak, $1.32/$3.96 peak). Effective 04:00 UTC Sept 10. Source: DeepSeek – Pricing
• Benchmarks now machine-readable: the change log and Hugging Face card publish exact V4.1-Flash scores (Terminal-Bench 2.1: 90.6, DeepSWE v1.1: 74.2, CyberGym: 88.1) versus named competitors, replacing the image-only tables criticized in earlier reports. Source: DeepSeek – Updates ; Hugging Face – Deepseek V4.1 Flash
• First-party harness: DeepSeek Harness ("dsh") is in developer preview with a Web UI, Python SDK, GitHub review sessions, MCP memory integration, and plugin development docs; a desktop app for macOS and Windows appeared in preview around Sept 29. Source: Deepseek-Harness – Quickstart ; News – Item
• Ecosystem: official partners WorkBuddy (including CodeBuddy) and OpenCode fully support V4.1-Flash at launch; the integrations index adds Qoder, and OpenCode Go ran a 4x usage promo on V4.1-Flash (community report). Sources: DeepSeek – News260910 ; News – Item
• Infrastructure paper (Sept 26): DeepSeek published DSec, its internal elastic compute platform: per scale unit ~160 CPU nodes, 30K cores, ~250 TB DRAM, ~3M sandbox instances served per day, peak concurrency ~380K, creation rate >5,000 instances/second. Source: News – Item
• Compute sovereignty (Sept 30): Reuters reported DeepSeek partnered with Huawei on chip programming tools to reduce Nvidia reliance, and DeepSeek open-sourced DeepGEMM-Ascend, its Ascend NPU matrix-multiplication kernel library. Sources: News – Item ; News – Item
• Alias status opaque: the August report recorded Oct 24, 2026 as the deprecation date for deepseek-chat/deepseek-reasoner; current docs no longer mention these aliases anywhere, and no live page documents a date. Status: undisclosed. Source: DeepSeek – Updates

Plans

DeepSeek is an API-only provider. There are no subscription plans, tiers, bundled coding agents, or free tier. Users top up a balance and are billed per token, with granted balance consumed before topped-up balance. Source: DeepSeek – Pricing

Concurrency limits:

Higher concurrency is available at no extra cost via a capacity-expansion request. Source: DeepSeek – Rate Limit

Terms explained:

• Concurrency limit - simultaneous in-flight requests per account, not a per-minute or per-day request cap; HTTP 429 on breach. Source: DeepSeek – Rate Limit

API Pricing

All prices per 1M tokens, verified live on 2026-09-30. Off-peak rates are 50% of peak; peak hours are 01:00-04:00 and 06:00-10:00 UTC, weekdays, excluding Chinese public holidays.

Notes:

• Flash prices took effect 04:00 UTC on 2026-09-10 with the V4.1-Flash launch ("More efficient architecture. Lower API prices."). August off-peak Flash was $0.22/$0.66.
• V4-Pro prices are unchanged from August. Pro continues to be served after the Sept 14 reroute plan was cancelled.
• Retired names deepseek-v4-flash and deepseek-v4-flash-vision-exp are billed at Flash prices.
• Both models support thinking and non-thinking modes at the same price; thinking mode may consume more tokens. FIM completion is non-thinking mode only.
• Vision is supported on Flash and not on Pro.
• Deduction rule: expense = tokens x price; prices may change at DeepSeek's discretion.

Source: DeepSeek – Pricing

Model Performance / Benchmarks

V4.1-Flash instruct results at maximum reasoning effort (reasoning_effort=100, temperature=1.0, top_p=0.95), from the official Hugging Face card. Code agent benchmarks use DeepSeek Harness Minimal mode with 1M context; DeepSWE v1.1 uses the mini-SWE harness; SEC-Bench Pro uses the Claude Code harness.

Harness comparison (V4.1-Flash across agent scaffolds, max effort): DeepSWE v1.1 resolved rates: mini-SWE 74.2, DSH Minimal 72.6, DSH Standard 70.5, Claude Code 69.8, Pi 66.2, Codex 65.6, OpenCode 65.5, DSH PTC 67.6. Terminal-Bench 2.1: DSH Minimal 90.6, mini-SWE 90.3, Claude Code 88.0, Pi 86.1, OpenCode 85.0, Codex 84.1. The spread between scaffolds (65.5 to 74.2 on DeepSWE) shows harness choice moves results by up to 8.7 points for the same model. Source: Hugging Face – Deepseek V4.1 Flash

Reading the table: V4.1-Flash leads or ties on 7 of 14 rows, but on the newest Terminal-Bench 3.0/4.0 suites it scores 30.0/31.2 versus Opus-5.0's 43.3/51.8, and it trails GPT-5.6 Sol on security-focused SEC-Bench Pro and ExploitGym. Community evaluations split the same way (see Community Signals). Source: Hugging Face – Deepseek V4.1 Flash

Latest News

V4.1-Flash Beta surfaces (September 8, 2026)

An internal-beta endpoint deepseek-v4.1-flash-expires-on-0910 appeared, priced like V4-Flash with a 20-concurrent-request account limit, letting API users test the model two days early. Source: News – Item

Pro-Rerouting Announcement (September 9, 2026)

A banner on the DeepSeek platform announced V4.1-Flash for ~Sept 10 and stated that "following the official launch of V4.1 Flash and prior to the release of V4.1 Pro, all requests to the Pro model will be routed to V4.1 Flash and billed at Flash's price." The HN thread reached 420 points and 218 comments, largely critical of forced model swaps. Source: News – Item

DeepSeek-V4.1-Flash Release and Flash Price Cut (September 10, 2026)

V4.1-Flash went live on the API with native multimodal support; V4-Flash and V4-Flash-Vision-Exp were retired with compatibility routing. New (lower) Flash pricing took effect 04:00 UTC. DeepSeek claims V4.1-Flash's KV cache needs 1/4 the HBM and 1/8 the SSD storage of the previous generation, and published full benchmark tables. Weights are MIT-licensed on Hugging Face with a technical report, a prompt-encoding reference implementation, and a Rust/Python "deepseek-recipe" toolkit. Source: DeepSeek – News260910 ; Hugging Face – Deepseek V4.1 Flash

V4-Pro Reprieve (September 10, 2026, change log)

The same-day change log entry reads: "In response to user demand, we have decided to continue providing API services for DeepSeek V4 Pro after September 14, 2026, with the billing method remaining unchanged. We will provide further notice should there be any changes." The pricing page continues to list Pro at $0.66/$1.98 off-peak. Source: DeepSeek – Updates

DeepSeek Harness Developer Preview (mid-September; desktop app ~September 29)

The docs now headline "DeepSeek Harness," a first-party agent harness in developer preview for "agent harness developers worldwide," with Web UI, Python SDK, GitHub review sessions, scheduled session reminders, and MCP memory integrations. A macOS/Windows desktop app appeared in preview around Sept 29 at deepseek.com/en/harness. This is DeepSeek's first move from model supplier to agent-platform supplier, and the harness was already used as the reference scaffold for official benchmark runs. Sources: DeepSeek , Deepseek-Harness – Quickstart , News – Item

"Best Hacking Model" Evaluations (September 16, 2026)

Security firm enclave.ai published "DeepSeek v4.1 Flash Is Now Our Best Hacking Model" (177 points on HN), consistent with the official CyberGym score of 88.1, the highest in DeepSeek's comparison table; the thread surfaced both strong praise and competing internal evaluations favoring GLM-5.3. Source: News – Item

DSec Elastic Compute Paper (September 26, 2026)

DeepSeek's systems paper on DSec, its internal elastic compute platform for agent sandboxes, disclosed per-scale-unit figures: ~160 CPU nodes, 30K cores, ~250 TB DRAM, ~3M sandbox instances per day, ~380K peak concurrency, >5,000 instance creations per second. The HN thread (323 points) read it as a signal of DeepSeek's infrastructure depth for agentic workloads. Source: News – Item

Huawei Partnership and DeepGEMM-Ascend (September 30, 2026)

Reuters reported DeepSeek and Huawei partnered on chip programming tools to reduce reliance on Nvidia, and DeepSeek open-sourced DeepGEMM-Ascend, its matrix-multiplication kernel library for Huawei Ascend NPUs. Sources: News – Item , News – Item

Community Signals

V4.1-Flash launch: 1,016 points, 574 comments (HN, Sept 10)

The launch thread was September's highest-engagement DeepSeek story. Reactions split three ways: architecture admiration, pricing scrutiny, and local-hardware disappointment. revolvingthrow on the size jump: "the original v4 flash was 284B, which was large but still somewhat reasonable for running locally. This one is 552B so almost twice that... it's not really flash anymore, imo." News – Item AlexWApp read DeepSeek's own table carefully: "V4.1 Flash is ahead on Terminal-Bench 2.1, DeepSWE, NL2Repo, and AutomationBench, but it is behind on GPQA Diamond, Terminal-Bench 3.0 and 4.0, and SEC-Bench Pro." News – Item k__ reported real-world throughput below beta claims: "while the throughput was 400-500tps in beta its now ~150tps on OpenRouter... it's still 100% faster for a very good price." News – Item SyneRyder repeated the standing privacy caveat: "if you want to try this via OpenRouter, DeepSeek openly trains on all of your prompts." News – Item k9294 highlighted the cache-hit economics: "I'm surprised more people aren't talking about the cache hit price: $0.003 per million tokens," pricing a real 447-turn coding task across rate scenarios. News – Item Thread: News – Item

Forced Pro-to-Flash rerouting: backlash, then a same-day reversal (HN, Sept 9; 420 points, 218 comments)

The community's strongest negative reaction of the month targeted the plan to silently swap deepseek-v4-pro for V4.1-Flash. simonw: "If I'd carefully tested and optimized prompts against Pro I wouldn't be keen on this particular news. I feel like API model providers should lean towards not swapping out models on their paying customers, no matter how much 'better' the new model is meant to be." News – Item aftbit: "Please don't do this kind of thing. If a user has validated a workflow on V4 Pro, they might not want to suddenly start testing it in production on V4.1 Flash." News – Item damsta: "While V4.1 Flash performance and cost looks promising this auto re-routing sounds concerning." News – Item DeepSeek's change-log reversal ("in response to user demand") landed the same day the reroute was announced. Thread: News – Item ; reversal: DeepSeek – Updates

Cost-in-practice: cents per task where rivals charge dollars (HN, Sept 16; 177 points, 67 comments)

On the enclave.ai hacking-model thread, pimeys gave the month's most-quoted cost comparison: "I've eval'd these models for weeks against Gemini 3.8, Kimi K3 and Opus 5, and DeepSeek absolutely wins these evals... If Kimi was about 30% of the price of Opus 5 for the same quality, DeepSeek is 1/10th of a price of Kimi K3... the cost per task is under a dollar, usually 15-30 cents. In comparison the same task with Kimi would be 3-15 dollars... with GPT 5.5 a 800 dollar task was not uncommon." News – Item TuxSH pushed back with a security workload: "GLM 5.3 founds almost all the vulns in 30min for $22, while DS only found one vuln for $2 in 40min." News – Item gertlabs placed V4.1-Flash on the price-performance frontier: "Because it's a heavy reasoner, it sits near Gemini 3.7 Flash on the Pareto front (not as cheap as the price suggests in practice)... Closer than expected to the top open weights models (GLM 5.3 and Kimi K3) in agentic coding, at lower cost." News – Item Thread: News – Item

DSec paper: 323 points, 116 comments (HN, Sept 26)

The infrastructure paper drew praise for scale and authorship breadth. swingboy: "Is there a lab more innovative than DeepSeek? Imagine if they had the same compute resources that Anthropic and OpenAI have." News – Item peter_d_sherman quoted the headline numbers: "a single scale unit serves about 3 M sandbox instances, with peak concurrency reaching ~380K and a creation rate exceeding 5,000 instances per second." News – Item Thread: News – Item

Other September signals

Self-hosting moved closer to mainstream: users reported V4.1-Flash serving in 192GB of vRAM (News – Item comment by hactually) and a 4xH200 server (~180K EUR) recommendation (News – Item comment by drdebug), while a 2020 M1 Mac Mini managed only 23 seconds/token (News – Item). A Show HN built a Blender coding harness on DeepSeek for $7.18 total, 3,833 requests, 613M tokens, 97% served from cache (News – Item). A third-party architecture deep-dive of the CED/CSA2 design gathered 131 points (News – Item). Just after the window, the DeepSeek Harness desktop app thread hit 382 points on Oct 2 (News – Item), and the Huawei Ascend programming stack open-sourcing continued the compute-sovereignty story (News – Item). Reddit search for DeepSeek community signals was blocked (login wall) and could not be used this cycle.

Reddit recovery (added 2026-10-03)

The distillation dispute reached Reddit's front pages. r/Anthropic (2.2K upvotes, 751 comments, ~Sep 15): "Deepseek engineer responds to dario and compares anthropic to... just read" Reddit – Deepseek Engineer Responds To Dario And Compares . u/ForwardLoop: "I was hoping for Star Trek. Turns out 'Enterprise' was the pricing tier." Reddit – P9Uqayf . u/v4bj: "Dario and Sam basically said we need to control this market for everyone's safety. Good on DeepSeek to throw down the gauntlet." Reddit – P9Uopaa . Counterpoint from u/A_Novelty-Account: "DeepSeek is just as self-interested as Anthropic and OpenAI, and they're well behind the 8-ball right now." Reddit – P9Ut88E . Community scale: r/DeepSeek 152K weekly visitors, 3.4K weekly contributions; r/DeepSeekHarness 2.2K weekly visitors.

Enterprise Readiness

Transparency Gaps