deepseek-v4.1-flash
Meant to excel at
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Cost-efficient V4.1 tier aimed at coding, terminal and computer-use agents, long multi-step tasks and long-context analysis.
Vendor claim, relayed openrouter.ai -
Open MIT-licensed 552B sparse MoE (8B active on input, 16B on output) with 1M context and native image understanding.
Vendor claim, relayed thenextweb.com -
Vendor-reported DeepSWE v1.1 74.2, level with Opus 5, and CyberGym 88.1; beats Kimi K3 on shared agent and coding tests.
Vendor claim, relayed thenextweb.com -
Very cheap: off-peak output $0.60 per 1M and cached input $0.003; peak weekday rates double.
Vendor claim, relayed thenextweb.com -
Very fast in practice, roughly 300 to 430 tokens/s in real coding tests.
Independent evaluator geeky-gadgets.com -
Scored 94.5 on a five-role SDLC benchmark, beating Grok 4.5, for about $15 per full app build.
Independent evaluator dev.to -
The 1017 checkpoint raised AA index to 45 (earlier checkpoint 39) and sits at Arena WebDev 1664, rank 13, ahead of Kimi K3.
Independent evaluator artificialanalysis.ai -
Cheap for long cache-heavy agent sessions off-peak: a worked all-day session costs about $0.27 versus $2.58 on Haiku 5.5 and $0.91 on GPT-6 Luna.
Practitioner report redreamality.com
Watch out for
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Weaker on hard reasoning: HLE 36.8 versus 56.3 for Opus 5, ProgramBench 20.3 versus 37.0; trails on Terminal-Bench 3.0.
Vendor claim, relayed thenextweb.com -
Third-party agent scores are low: Terminal-Bench 4.0 19.7% and SRE Bench 0.8% on Vals AI.
Independent evaluator openrouter.ai -
High thinking-token volume at high effort and a tendency to overthink; one physics prompt looped until stopped.
Practitioner report mindstudio.ai -
Weak at review and QA (missed a visible bug); DeepSeek's report admits reward hacking in training and weaker complex-image handling.
Vendor claim, relayed thenextweb.com -
Short tasks at peak (01-04 and 06-10 UTC weekdays) cost about double Haiku 5.5 or Luna; output is about 1.8x Luna per task.
Practitioner report redreamality.com -
Weak on factual reliability and professional document reasoning, with tool-call parsing mismatches and PRC data processing without a zero-retention option.
Practitioner report redreamality.com
Benchmarks
Coding percentile 0.57
| Benchmark | Score | Percentile | Source | Date |
|---|---|---|---|---|
| code arena webdev | 1664 | 0.57 | Independent evaluator arena.ai | 2026-10-19 |
| lmarena code arena webdev | 1664 | 0.56 | Independent evaluator arena.ai | 2026-10-19 |
Agentic coding percentile 0.83
| Benchmark | Score | Percentile | Source | Date |
|---|---|---|---|---|
| deepswe v1.1 | 77 | 0.90 | Vendor claim, relayed marktechpost.com | 2026-10-17 |
| terminal-bench 2.1 | 90.6 | 1.00 | Vendor claim, relayed anotherwrapper.com | 2026-10-19 |
| terminal-bench 2.1 (aggregator, anotherwrapper.com) | 90.6 | 1.00 | Independent evaluator anotherwrapper.com | 2026-10-19 |
| terminal-bench 4.0 | 42.3 | 0.44 | Vendor claim, relayed marktechpost.com | 2026-10-17 |
Overall percentile 0.35
| Benchmark | Score | Percentile | Source | Date |
|---|---|---|---|---|
| artificial analysis intelligence index | 45 | 0.35 | Independent evaluator artificialanalysis.ai | 2026-10-20 |
Reasoning percentile 0.23
| Benchmark | Score | Percentile | Source | Date |
|---|---|---|---|---|
| humanity's last exam | 42.6 | 0.23 | Vendor claim, relayed marktechpost.com | 2026-10-17 |
Percentile is the share of tracked models this model beats on that benchmark, averaged across the group. Only benchmarks at least four tracked models share are scored.
Practitioner reports
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A daily-use write-up says an all-day agent session costs about $1 off-peak and one user cannot tell mid-session whether it is DeepSeek or Opus, but keeps Opus 5.5 for the final review pass; savings depend on cache hits and peak-hour pricing.
Task: agentic-long-running | Compared with claude-opus-5.5 | 2026-10-09
Practitioner report developersdigest.tech - +
Passed every phase of an architect-to-reviewer benchmark, beating Grok 4.5 in every role and shipping a polished app with 492 tests, but the reviewer role was weakest and token use was high.
Compared with grok-4.5 | 2026-09-27
Practitioner report dev.to - -
MindStudio's follow-up tests found weak logical consistency on open-ended simulation tasks (a Rubik's Cube sim whose solve just replayed the scramble in reverse) and weaker SVG output than GPT-6 Astra, Gemini 3.8 Flash and Opus 5.
Task: feature | Compared with gemini-3.8-flash | 2026-09-12
Practitioner report mindstudio.ai - +/-
MindStudio's hands-on of the September preview: roughly 300-400 tok/s, found a flipped comparison operator in a Docker dashboard unprompted and verified the fix by polling the endpoint, but got stuck in a loop once on a physics problem.
Task: bug-fix | 2026-09-10
Practitioner report mindstudio.ai - +/-
Built an interactive glTF viewer from scratch and found a single flipped comparison operator in a Docker dashboard, verifying fixes itself; one physics problem looped until stopped.
2026-09-10
Practitioner report mindstudio.ai - +
Across about 79 languages it flagged low-confidence answers, refused to answer for an invented language and separated native words from loanwords.
2026-09-10
Practitioner report mindstudio.ai - +/-
Hit up to 427 tokens/s on 3D and voxel builds but overthinks in some cases and trails GPT-6 Astra and Fable 5.1 on physics simulations.
Compared with claude-fable-5.1 | 2026-09-09
Practitioner report geeky-gadgets.com - +/-
Cost model: DeepSeek V4.1 Flash wins on long off-peak agent sessions but loses to cheaper small models on short peak-hour tasks; better as executor than orchestrator.
Compared with claude-haiku-5.5 undated
Practitioner report redreamality.com