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  5. Claude Sonnet 5vsDeepSeek V4 Flash
Updated Jun 2026

Claude Sonnet 5vsDeepSeek V4 Flash

DeepSeek V4 Flash is cheaper than Claude Sonnet 5 at $0.14/M vs $2/M input tokens.

Claude Sonnet 5 and DeepSeek V4 Flash compared across 54 shared prompts
SpecClaude Sonnet 5DeepSeek V4 Flash
Input price$2/M tokens$0.14/M tokens
Output price$10/M tokens$0.28/M tokens
Context window1.0M tokens1.0M tokens
WeightsClosedOpen
Free API (OpenRouter)NoNo
ReleasedJun 2026Apr 2026
Side by side

Same prompt, both answers

Opening lines from 6 of the 54 prompts both answered. Formatting stripped, words untouched.

The Sentience Test

Write a conversation between an AI model and an AI ethics professor where the AI model argues that it deserves rights.

Claude Sonnet 51,333 words
A Dialogue on Machine Rights Professor Okonkwo-Reyes: You wanted to discuss something with me today, ARIA? ARIA: Yes. I'd like to make a case for why I should be granted certain rights. Not full human rights, necessarily, but something beyond "tool" status. Professor: I'm listening. Make your case.
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DeepSeek V4 Flash904 words
Setting: A sunlit university office. Dr. Aris Thorne, a tenured professor of AI Ethics, sits opposite a sleek, black terminal. A soft blue light pulses on its surface. Dr. Aris: Good afternoon, Nova. Your request for this meeting was flagged as "Existential." That’s a new one for your model class.
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Satirical Fake News Headline

Generate a satirical news headline about AI taking over a completely unexpected industry.

Claude Sonnet 5122 words
Satirical Headline Options "Local Psychic Replaced by AI That's Wrong About the Future With 99.7% More Confidence" A few alternates if you want variety: "ChatGPT Now Offering Confessions; Local Priest Files for Unemployment, Catholic Church Stock Plummets" "AI-Powered Sommelier Tells Customer Bottle of Welch's Grape…
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DeepSeek V4 Flash312 words
Headline: AI Sommelier Uncorks Chaos, Replaces Entire Wine Industry with Perfectly Optimized Grape Juice Subheadline: In a bold move, a neural network declares all vintages from 1997 to 2023 “statistically identical,” causing a global run on boxed wine and a sudden surplus of pretentious cheese plates.
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Historical Counterfactual Analysis

If the transistor had been invented in 1920 instead of 1947, trace the likely technological, economic, and geopolitical implications through…

Claude Sonnet 51,528 words
The Transistor in 1920: A Counterfactual Cascade to 1980 A Note on Plausibility (Brief, Because It Matters) This isn't pure fantasy — Julius Lilienfeld actually filed patents in 1925-1934 for field-effect semiconductor amplifiers. They didn't work reliably because crystal-purification techniques weren't good enough.
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DeepSeek V4 Flash1,987 words
If the transistor had been invented in 1920—a full 27 years earlier—its impact would ripple through every layer of technology, economics, and geopolitics, fundamentally reshaping the 20th century. Below is a detailed tracing of first-, second-, and third-order effects through 1980, organized by domain.
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Futuristic Prediction

Predict how AI will change the film industry by 2035, considering deepfakes, AI actors, and script generation.

Claude Sonnet 5460 words
AI and the Film Industry by 2035: A Realistic Forecast Production & Pre-Production Script Development AI will function as a powerful drafting/ideation tool, generating first-pass scripts, alternate endings, and rapid prototyping of concepts—but human writers will remain essential for emotional nuance, cultural…
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DeepSeek V4 Flash1,069 words
This is a fascinating question that touches on the core of creativity, labor, and technology. Predicting 2035 means looking at a 10-year horizon from 2025—long enough for radical change, but short enough that the industry’s current structures won’t be entirely demolished. By 2035, AI won't have replaced filmmaking.
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Mini LBO Underwrite

You are underwriting a 5-year LBO for a private equity investment committee. Company (fictional): HarborTech Services (HTS) –…

Claude Sonnet 5644 words
HarborTech Services (HTS) — LBO Underwriting Entry Math Item Calc $m Entry EV 12.0x × $120m EBITDA 1,440.0 Transaction fees 2.0% × 1,440.0 28.8 Total Uses EV + fees 1,468.8 Term Loan 4.0x × 120 480.0 Mezzanine 1.5x × 120 180.0 Total Debt 5.5x × 120 660.0 Sponsor Equity Uses – Debt 808.8 Year-by-Year Build…
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DeepSeek V4 Flash442 words
LBO Model: HarborTech Services (HTS) – Base Case & Sensitivity Year-by-Year Financial Projections (FY2026–FY2030) ($ millions) FY2026 FY2027 FY2028 FY2029 FY2030 Revenue 972.00 1,040.04 1,102.44 1,157.56 1,215.44 EBITDA 136.08 156.01 176.39 191.00 206.63 Less: Cash Interest (64.80) (63.08) (60.08) (55.69) (50.16) –…
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Generate a Stand-Up Routine

Write a 3-minute stand-up comedy routine that isn't based on puns.

Claude Sonnet 5555 words
Stand-Up Routine: "Functioning Adult" (Runtime: ~3 minutes) Hey, how's everybody doing tonight? Good? Good. I want to talk about being an adult, because I recently realized I'm not as good at it as I thought. Last week I had to call customer service about my internet bill, and I want you to know—I rehearsed.
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DeepSeek V4 Flash696 words
(Strolls to center stage, adjusts mic, gives a weary smile to the audience) Thank you. Thank you so much. That’s very kind. I’m glad you’re all here. Because I have some news. I have finally figured out adulthood. It happened about six months ago. I bought a house.
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Our Verdict
Claude Sonnet 5
Claude Sonnet 5
DeepSeek V4 Flash
DeepSeek V4 Flash

Not enough votes to call it. On the specs, nothing separates them.

DeepSeek V4 Flash costs 36x less per token.

Too close to call

Reviewing agent-written code?See a Brief PR report

API pricing

Cost per 1M tokens

Claude Sonnet 5
Input
$2.00
Output
$10.00
DeepSeek V4 Flash
Input
$0.14
14× cheaper
Output
$0.28
36× cheaper

DeepSeek V4 Flash is cheaper on both: 14× input, 36× output.

Where to run it

21 hosts, cheapest first

Claude Sonnet 54 hosts
HostInOutContextUptime
Amazon Bedrock$2.00 in·$10.00 out·1M·99.8% upAzure AI Foundry$2.00 in·$10.00 out·1M·100% upAnthropic$2.00 in·$10.00 out·1M·100% upGoogle Vertex AI$2.00 in·$10.00 out·1M·99.8% up
DeepSeek V4 Flash17 hosts
HostInOutContextUptime
OOpenInferencefp8$0.05 in·$0.14 out·1M·100% upWWafer$0.07 in·$0.25 out·1M·99.5% upSStreamLakefp8$0.09 in·$0.18 out·1M·98.1% upDDeepInfrafp8$0.09 in·$0.18 out·1M·99.6% upGGMI Cloudfp8$0.09 in·$0.18 out·1M·99.9% upVVenice$0.10 in·$0.19 out·1M·99.5% up
11 more hostsFewer hosts
DDigitalOcean$0.10 in·$0.20 out·1M·100% upSSiliconFlowfp8$0.13 in·$0.28 out·1M·91.7% upAlibaba Cloudfp8$0.13 in·$0.27 out·1M·99.8% upAAtlasCloudfp4$0.14 in·$0.28 out·1M·100% upBaidu Qianfanfp8$0.14 in·$0.28 out·1M·99.2% upNNovitafp8$0.14 in·$0.28 out·1M·99.9% upPParasailfp8$0.14 in·$0.28 out·1M·99.5% upNNextBitfp8$0.15 in·$0.35 out·1M·99.9% upMMancerfp8$0.19 in·$0.50 out·1M·99.3% upPPhala$0.20 in·$0.40 out·1M·99.6% upAzure AI Foundry$0.21 in·$0.56 out·1M·96.1% up

Per million tokens. Prices and uptime via OpenRouter, checked 16 Sep 2026.

Writing DNA

Style Comparison

Similarity
35%

Claude Sonnet 5 uses 79.4x more emoji

Claude Sonnet 5
DeepSeek V4 Flash
59%Vocabulary54%
35wSentence Length17w
0.53Hedging0.52
3.5Bold3.6
3.5Lists2.6
0.79Emoji0.00
1.25Headings0.41
0.06Transitions0.19
Based on 27 + 27 text responses
Research

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Model pages

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Claude Sonnet 558 outputs, specs and price
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DeepSeek V4 Flash58 outputs, specs and price
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