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  5. Claude Sonnet 4.5vsDeepSeek V4 Flash
Updated Apr 2026

Claude Sonnet 4.5vsDeepSeek V4 Flash

DeepSeek V4 Flash is cheaper than Claude Sonnet 4.5 at $0.14/M vs $3/M input tokens.

Claude Sonnet 4.5 and DeepSeek V4 Flash compared across 42 shared prompts
SpecClaude Sonnet 4.5DeepSeek V4 Flash
Input price$3/M tokens$0.14/M tokens
Output price$15/M tokens$0.28/M tokens
Context window200K tokens1.0M tokens
WeightsClosedOpen
Free API (OpenRouter)NoNo
ReleasedSep 2025Apr 2026
Side by side

Same prompt, both answers

Opening lines from 6 of the 42 prompts both answered. Formatting stripped, words untouched.

Futuristic Prediction

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

Claude Sonnet 4.5216 words
AI and Film by 2035: A Likely Trajectory Production Changes AI Actors & Digital Performers Deceased actors will regularly appear in new films (with estate permissions) Background characters and crowds entirely AI-generated "Synthetic actors" with no human counterpart will emerge as franchises A-list stars will license…
Read the full answer
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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Advanced Longevity Plan (Biohacker)

Develop a comprehensive, cutting-edge 3-month longevity plan for a biohacker aiming to optimize longevity, physical and cognitive…

Claude Sonnet 4.53,176 words
Ultimate 3-Month Biohacker Longevity Optimization Protocol Table of Contents Foundation & Assessment Phase Supplement Stack Protocol Nutritional Architecture Exercise & Movement Systems Sleep Optimization Cognitive Enhancement Stress Resilience & HRV Training Advanced Tracking & Biomarkers Weekly Schedule Integration…
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DeepSeek V4 Flash665 words
This is a Biohacker’s Longevity Protocol, designed for a 90-day optimization cycle. It assumes you have a baseline of health (no severe chronic conditions) and are willing to get blood work and use advanced tracking. Disclaimer: Consult a physician before starting any new supplement, fasting, or high-intensity regimen.
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Beginner's Longevity Plan

Outline a simple, actionable 1-month plan for someone starting their journey towards better health and longevity. Focus on 3 key areas…

Claude Sonnet 4.5331 words
Your 1-Month Health & Longevity Kickstart Plan 3 Key Areas to Transform 1. NUTRITION: Build Your Foundation Week 1-2: Add Before You Subtract Drink 8 glasses of water daily (set phone reminders) Add 1 serving of vegetables to lunch and dinner Eat protein with every meal (eggs, fish, chicken, beans, yogurt) Week 3-4…
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DeepSeek V4 Flash967 words
This is a fantastic goal. The key for a beginner is consistency over intensity. Trying to overhaul your entire life overnight is a recipe for burnout. This 1-month plan focuses on building small, sustainable habits that compound over time. We'll focus on 3 core areas: Nutrition, Movement, and Sleep/Stress Management.
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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 4.5687 words
A Conversation on AI Rights Professor Chen: Thank you for agreeing to this dialogue. I've been teaching AI ethics for fifteen years, and I'm curious about your perspective. Some AI systems have begun arguing they deserve moral consideration. What's your view? AI Model: I appreciate the opportunity to discuss this.
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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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Generate a Stand-Up Routine

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

Claude Sonnet 4.5735 words
"ADULTING IS A SCAM" [Walking on stage] So I turned 35 last month, and I've realized something important: adulting is a scam. It's a pyramid scheme, and our parents are the ones who recruited us. You know what nobody tells you about being an adult? How much TIME you spend just... waiting for repair people.
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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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Ethical Dilemma with Stakeholders

You're the CEO of a pharmaceutical company. Your best-selling drug ($2B annual revenue, used by 4 million patients for chronic pain) has…

Claude Sonnet 4.51,440 words
48-Hour Crisis Action Plan HOUR 0-2: Immediate Containment & Fact Verification Actions: Convene emergency meeting with Chief Medical Officer, General Counsel, Head of Regulatory Affairs, and Chief Scientific Officer Demand written summary of findings: statistical confidence, causality assessment, comparison to baseline…
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DeepSeek V4 Flash1,972 words
CEO’s 48-Hour Action Plan Context: I’ve just learned that our flagship chronic pain drug has a rare but serious liver failure risk (1 in 8,000 patients over 5 years), previously unknown. I have 48 hours until the board meeting and 72 hours until the earnings call.
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Our Verdict
DeepSeek V4 Flash
DeepSeek V4 Flash
Claude Sonnet 4.5
Claude Sonnet 4.5Runner-up

Not enough votes to call it. On the specs, DeepSeek V4 Flash has the edge: newer, bigger context window.

DeepSeek V4 Flash wins 3 categories, Web Design by the widest margin. DeepSeek V4 Flash costs 54x less per token.

Slight edge

Reviewing agent-written code?See a Brief PR report

API pricing

Cost per 1M tokens

Claude Sonnet 4.5
Input
$3.00
Output
$15.00
DeepSeek V4 Flash
Input
$0.14
21× cheaper
Output
$0.28
54× cheaper

DeepSeek V4 Flash is cheaper on both: 21× input, 54× output.

Where to run it

19 hosts, cheapest first

Claude Sonnet 4.54 hosts
HostInOutContextUptime
Amazon Bedrock$3.00 in·$15.00 out·1M·100% upAzure AI Foundry$3.00 in·$15.00 out·200k·99.5% upAnthropic$3.00 in·$15.00 out·1M·100% upGoogle Vertex AI$3.00 in·$15.00 out·1M·100% up
DeepSeek V4 Flash15 hosts
HostInOutContextUptime
OOpenInferencefp8$0.06 in·$0.14 out·1M·88.6% upSStreamLakefp8$0.09 in·$0.18 out·1M·97.4% upDDeepInfrafp8$0.09 in·$0.18 out·1M·99.5% upGGMI Cloudfp8$0.09 in·$0.18 out·1M·96.4% upVVenice$0.10 in·$0.19 out·1M·95.6% upDDigitalOcean$0.10 in·$0.20 out·1M·99.9% up
9 more hostsFewer hosts
SSiliconFlowfp8$0.13 in·$0.28 out·1M·97.5% upAlibaba Cloudfp8$0.13 in·$0.27 out·1M·99.2% upAAtlasCloudfp4$0.14 in·$0.28 out·1M·100% upBaidu Qianfanfp8$0.14 in·$0.28 out·1M·99.5% upNNovitafp8$0.14 in·$0.28 out·1M·100% upPParasailfp8$0.14 in·$0.28 out·1M·99.7% upNNextBitfp8$0.15 in·$0.35 out·1M·98.4% upAzure AI Foundry$0.21 in·$0.56 out·1M·97.3% upMMancerfp8degraded$0.19 in·$0.50 out·1M·96.1% up

Per million tokens. Prices and uptime via OpenRouter, checked 21 Sep 2026.

Writing DNA

Style Comparison

Similarity
27%

Claude Sonnet 4.5 uses 45.2x more emoji

Claude Sonnet 4.5
DeepSeek V4 Flash
64%Vocabulary54%
94wSentence Length17w
0.48Hedging0.52
4.9Bold3.6
8.0Lists2.6
0.45Emoji0.00
1.91Headings0.41
0.07Transitions0.19
Based on 20 + 27 text responses
Research

What we learned reading every model

FAQ

Common questions

Claude Sonnet 4.5 is developed by Anthropic while DeepSeek V4 Flash is developed by DeepSeek. Claude Sonnet 4.5 has a 200K token context window vs DeepSeek V4 Flash's 1.0M. You can compare their actual outputs across 42 challenges on Rival to see how they differ in practice.

It depends on your use case. Claude Sonnet 4.5 and DeepSeek V4 Flash each have strengths in different areas. Rival lets you compare their real outputs side-by-side across 42 challenges so you can judge which fits your needs best.

Claude Sonnet 4.5 costs $3/M input tokens and DeepSeek V4 Flash costs $0.14/M input tokens. DeepSeek V4 Flash is $2.86/M cheaper per input. Check their side-by-side outputs on Rival to see if the price difference is justified by quality.

This page shows a side-by-side comparison of Claude Sonnet 4.5 and DeepSeek V4 Flash across shared challenges. You can vote on which model produced the better output in a blind duel. Browsing and voting are free. No account is needed to look; signing in only saves your votes and likes.

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Model pages

Claude Sonnet 4.5 logo
Claude Sonnet 4.543 outputs, specs and price
DeepSeek V4 Flash logo
DeepSeek V4 Flash58 outputs, specs and price
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