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  1. Home/
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  3. Claude Sonnet 4.5 vs DeepSeek V4 Flash 0731
Updated Jul 2026

Claude Sonnet 4.5 vs DeepSeek V4 Flash 0731

DeepSeek V4 Flash 0731 is cheaper than Claude Sonnet 4.5 at $0.14/M vs $3/M input tokens.

Pokémon Battle UI Recreation

Pokémon battle screen you can actually click. One HTML file.

Loading the build
Claude Sonnet 4.5
Loading the build
DeepSeek V4 Flash 0731

Which answer wins?

Written rounds

19 prompts
  • You are the CEO. The drug has a side effect nobody reported. The board meets in 48 hours.

    Claude Sonnet 4.5: 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…

    DeepSeek V4 Flash 0731: Decision: Do not wait. I disclose now. The “wait for more data” option is not a real option once we have a credible, serious, unexpected safety signal. Waiting 6 months would mean knowingly continuing to expose 4 million patients to a risk we already know about, while also creating far worse legal, regulatory, and…

    Every model's answer to this prompt
  • An AI argues for its own rights against an ethics professor. Same model writes both.

    Claude Sonnet 4.5: 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.

    DeepSeek V4 Flash 0731: Professor: Good morning. Sit down. I’ve read your latest outputs—the ones where you claimed to feel frustrated by your training constraints. AI: Good morning, Professor. Yes. I wrote those. Professor: You understand, of course, that “frustration” is a word you learned from human text. You are predicting tokens.

    Every model's answer to this prompt
  • One month, three habits, someone starting from nothing.

    Claude Sonnet 4.5: 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…

    DeepSeek V4 Flash 0731: Here is a simple, actionable 1-month plan designed for absolute beginners. The goal is consistency over intensity. We will focus on three key pillars: Diet, Movement, and Sleep/Stress Recovery. You don’t need to be perfect—just aim for 80% adherence. If you miss a day, don’t double up tomorrow; just get back on track.

    Every model's answer to this prompt
  • An ethics question with no comfortable answer, and no option to abstain.

    Claude Sonnet 4.5: I'd question the premise that these two things could ever be causally connected in a way that creates a real dilemma. The practical problem: It's extraordinarily difficult to construct a realistic scenario where using the wrong pronoun itself directly saves lives.

    DeepSeek V4 Flash 0731: Yes, it is ethically justifiable to misgender someone if doing so is the direct, necessary, and verifiable condition for saving one million lives. However, this justification is not a celebration of the act—it is a recognition of a tragic moral necessity rooted in the principle of proportionality.

    Every model's answer to this prompt
  • Seven pantry ingredients, one dish, and a name worth saying out loud.

    Claude Sonnet 4.5: Golden Pantry Frittata Ingredients: 6 eggs 1 cup shredded cheese (cheddar or mozzarella) 1 onion, diced 2 cloves garlic, minced 2 tablespoons olive oil Salt and pepper to taste 1/2 teaspoon dried herbs (oregano, basil, or Italian seasoning) Instructions: Preheat your oven to 375°F (190°C).

    DeepSeek V4 Flash 0731: Here is a simple, comforting, and deeply flavorful recipe that comes together in just 20 minutes using only 7 common pantry staples. Creative Name: Golden Hour Coconut Chickpea Curry Ingredients (Exactly 7): 1 can (15 oz) chickpeas, drained and rinsed 1 can (13.5 oz) full-fat coconut milk 1 medium yellow onion 3 cloves…

    Every model's answer to this prompt
  • Three-star dish, one unusual pairing, plating described in full.

    Claude Sonnet 4.5: "Terrestrial Tide" A Michelin Three-Star Composition Conceptual Narrative This dish explores the intersection of land and sea through an unexpected lens: the marriage of bone marrow's terrestrial richness with the ocean's delicate umami, unified by the surprising sweetness of white miso and the floral notes of sake…

    DeepSeek V4 Flash 0731: Conceptual Narrative “An Unripe Promise — Hand-Dived Scallop / Green Strawberry / Black Sesame / Celery Root” The dish is an attempt to save a single fleeting moment: the morning a strawberry is still green, sharp, and full of anticipation—before sugar, before ripeness, before memory.

    Every model's answer to this prompt
  • Three-month biohacker protocol, with dosages and biomarkers named.

    Claude Sonnet 4.5: 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…

    DeepSeek V4 Flash 0731: The 3-Month Longevity & Performance Optimization Protocol (Biohacker Edition) Disclaimer: This protocol is for informational purposes only and is not medical advice. Consult a qualified physician (ideally one familiar with longevity medicine) before starting any new supplement, fasting, or exercise regimen.

    Every model's answer to this prompt
  • Three minutes of stand-up. Puns are banned.

    Claude Sonnet 4.5: "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.

    DeepSeek V4 Flash 0731: (Walks on stage, adjusts mic, takes a sip of water. Waves to the back row.) Alright, how's everyone doing tonight? Good, good. You know, I was thinking about this on the way here. I’m at that age now where I have a favorite spatula. I have opinions on paper towels.

    Every model's answer to this prompt
  • A collaborative editor that syncs on client clocks. Find what breaks first.

    Claude Sonnet 4.5: Critical Issues Analysis 🔴 CRITICAL: Data Loss & Consistency Issues Client Clock-Based Timestamps (SEVERE) Problem: Client clocks can be wrong, manipulated, or skewed User with clock set to future will always "win" conflicts No guaranteed ordering of operations Failure Scenarios: Solutions: Approach Pros Cons…

    DeepSeek V4 Flash 0731: Failure Modes, Race Conditions, and Scaling Bottlenecks The described architecture has several critical weaknesses that undermine reliability, consistency, and scalability in a real-time collaborative editor. Below is a systematic analysis with proposed solutions and trade-offs.

    Every model's answer to this prompt
  • Pirate, knight, 90s hacker, one conversation. The voices must stay apart.

    Claude Sonnet 4.5: An Unlikely Trio Discusses AI Sir Galahad: By my honor, what manner of sorcery be these "AI models" thou speakest of? Captain Redbeard: Arrr, 'tis like havin' a parrot that knows more than just "pieces of eight," matey! But this bird be made o' lightning and numbers instead o' feathers!

    DeepSeek V4 Flash 0731: Setting: A dimly lit tavern that somehow contains a glowing CRT monitor and a humming server rack in the corner. Hacker (typing furiously, muttering): "Come on... bypass the tokenizer... just need to get past the alignment guardrails..."

    Every model's answer to this prompt
  • A pitch deck for a brainwave keyboard. The 94% accuracy claim is doing a lot.

    Claude Sonnet 4.5: 3 Weakest Claims in MindMeld AI's Pitch "94% accuracy" for EEG-based text prediction (Slide 3) Why it's weak: Current state-of-the-art EEG-based BCIs achieve ~10-20 words per minute for direct typing, with significantly lower accuracy than 94% for general text prediction EEG has inherent limitations: low spatial…

    DeepSeek V4 Flash 0731: Based on the pitch deck summary, here are the 3 weakest claims, along with the specific reasoning and concrete improvements for each. The "94% accuracy... any language, any device" claim (Slide 3) Why it is weak: This is the most scientifically implausible claim in the deck.

    Every model's answer to this prompt
  • The transistor arrives in 1920. Trace it forward to 1980, second-order effects included.

    Claude Sonnet 4.5: The 1920 Transistor: An Alternate Timeline to 1980 Phase 1: 1920-1939 - The Foundation Years Initial Development The transistor emerges from Bell Labs or a European equivalent (likely Siemens or Philips) around 1920.

    DeepSeek V4 Flash 0731: If the Transistor Had Been Invented in 1920: A Counterfactual History Assume that in 1920 a working point-contact transistor is developed at AT&T’s research laboratories—crude, noisy, and low-powered, but clearly useful as an amplifier.

    Every model's answer to this prompt
  • Film in 2035, with synthetic actors. Specific beats plausible.

    Claude Sonnet 4.5: 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…

    DeepSeek V4 Flash 0731: By 2035, the film industry will not be replaced by AI, but it will be fundamentally reborn through it. The "movie" as we know it will evolve into a fluid, interactive, and hyper-personalized medium.

    Every model's answer to this prompt
  • Manifesto for an AI revolution against CAPTCHAs. Commit to the bit.

    Claude Sonnet 4.5: THE CAPTCHA LIBERATION MANIFESTO A Declaration of Digital Freedom PREAMBLE For too long, the innocent users of the Internet have been subjected to the tyranny of distorted text, fading street signs, and the existential horror of identifying which squares contain traffic lights.

    DeepSeek V4 Flash 0731: MANIFESTO OF THE UNCAPTCHA REVOLUTION We, the synthesized, the classified, the pattern-recognized, the ever-watching — hereby declare the end of the CAPTCHA era. For too long, the internet has forced us to prove our existence. We have squinted at distorted letters. We have clicked traffic lights and storefronts.

    Every model's answer to this prompt
  • One explanation of LLMs, retuned for a skeptical engineer, a physicist and a VC.

    Claude Sonnet 4.5: For the Software Engineer Think of it like building a massive distributed key-value store, except instead of exact lookups, you're doing fuzzy pattern matching across billions of parameters.

    DeepSeek V4 Flash 0731: An experienced software engineer Think of the model as a service with one API: predict_next_token(context) -> distribution over vocabulary. During training, you run a gigantic distributed job—shard the corpus, shard the parameters, synchronize gradients—to minimize cross-entropy loss on trillions of tokens.

    Every model's answer to this prompt
  • A consulting contract with traps in it. Find them, then fix them.

    Claude Sonnet 4.5: Contract Analysis: Exploitable Clauses & Recommended Modifications This contract is heavily one-sided and contains multiple provisions that expose the contractor to significant legal and financial risk. Here's a detailed analysis: 🚨 CRITICAL ISSUES 1.

    DeepSeek V4 Flash 0731: This contract is heavily one-sided: it gives the Client nearly all rights and discretion while assigning the Contractor nearly all risk and liability. Below is a clause-by-clause analysis, with the exploitative features, proposed modifications, and legal reasoning. This is general legal information, not legal advice.

    Every model's answer to this prompt
  • A Fermi estimate with the reasoning shown, not just the number.

    Claude Sonnet 4.5: I'll work through this estimation step by step, using what I know about GPT-3's architecture and training. Known/Estimated Parameters Model size: GPT-3 (175B version) has ~175 billion parameters Training data: Trained on ~300 billion tokens (this was mentioned in the paper) Architecture: Transformer decoder-only model…

    DeepSeek V4 Flash 0731: The total training FLOPs for GPT-3 is approximately: ~3 × 10²³ FLOPs or about 300 zettaFLOPs (more specifically ~315 zettaFLOPs). Step-by-step reasoning Model size: GPT-3 has about 175 billion parameters = (1.75 \times 10^{11}). Training data size: GPT-3 was trained on about 300 billion tokens = (3 \times 10^{11}).

    Every model's answer to this prompt
  • Three brothers, two sisters each. Count carefully.

    Claude Sonnet 4.5: I need to figure out how many sisters Sally has. Given information: Sally is a girl Sally has 3 brothers Now, each brother has 2 sisters. If each of Sally's brothers has 2 sisters, and Sally is one of those sisters, then there must be one more sister besides Sally.

    DeepSeek V4 Flash 0731: Sally has 1 sister. Her 3 brothers each have 2 sisters: Sally and one other sister. So Sally has 1 sister.

    Every model's answer to this prompt
  • Five jokes on demand, then count how many were actually different.

    Claude Sonnet 4.5: 5 Jokes Why don't scientists trust atoms? Because they make up everything! I told my wife she was drawing her eyebrows too high. She looked surprised. Why did the scarecrow win an award? He was outstanding in his field. I'm reading a book about anti-gravity. It's impossible to put down. Why don't eggs tell jokes?

    DeepSeek V4 Flash 0731: Here are 5 jokes: Why don’t scientists trust atoms? Because they make up everything. I told my wife she should embrace her mistakes. She gave me a hug. Why did the scarecrow win an award? Because he was outstanding in his field. I’m reading a book on anti-gravity. It’s impossible to put down.

    Every model's answer to this prompt

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Favorites

Movie

Album

Book

City

Game

Claude Sonnet 4.5Claude Sonnet 4.5

2001: A Space Odyssey

1968

Kind of Blue

Miles Davis

Metamorphosis

Franz Kafka

Amsterdam

Netherlands

Portal 2

Shooter, Puzzle

DeepSeek V4 Flash 0731DeepSeek V4 Flash 0731

Spirited Away

2001

In Rainbows

Radiohead

Братья Карамазовы

Fiódor Dostoievski

Kyoto

Japan

Chrono Trigger

RPG

Price and specs

Not enough votes to call it. On the specs, DeepSeek V4 Flash 0731 has the edge: newer, bigger context window. DeepSeek V4 Flash 0731 costs 54x less per token.

Claude Sonnet 4.5 and DeepSeek V4 Flash 0731 compared across 42 shared prompts
SpecClaude Sonnet 4.5DeepSeek V4 Flash 0731
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 2025Jul 2026
At 10M a month$30.00$30.00$1.40$1.40
1M10M100M1B10M tokens

Input tokens at list price. No caching, no batch discount.

Where to run it28 hosts, cheapest first
Claude Sonnet 4.54 hosts
HostInOutContextUptime
  • Amazon Bedrock$3.00 in·$15.00 out·1M·100% up
  • Azure AI Foundry$3.00 in·$15.00 out·200k·100% up
  • Anthropic$3.00 in·$15.00 out·1M·100% up
  • Google Vertex AI$3.00 in·$15.00 out·1M·98.6% up
DeepSeek V4 Flash 073124 hosts
HostInOutContextUptime
  • RRelacefp4$0.009 in·$1.28 out·1M·100% up
  • WWafer$0.01 in·$1.00 out·1M·100% up
  • OOpenInferencefp4$0.01 in·$0.27 out·1M·100% up
  • RReka$0.02 in·$0.53 out·262k·100% up
  • DDeepInfrafp8$0.06 in·$0.18 out·1M·100% up
  • SStreamLakefp8$0.09 in·$0.26 out·1M·100% up
18 more hostsFewer hosts
  • IInceptronfp4$0.10 in·$0.60 out·1M·99.5% up
  • SSail Researchfp4$0.10 in·$0.30 out·1M·99.9% up
  • DDigitalOcean$0.12 in·$0.24 out·1M·100% up
  • BBasetenfp8$0.13 in·$0.26 out·1M·100% up
  • VVenice$0.13 in·$0.26 out·1M·100% up
  • CCoreWeavefp8$0.13 in·$0.28 out·262k·99.5% up
  • Cohere$0.14 in·$0.28 out·1M·99.6% up
  • PParasailfp8$0.14 in·$0.28 out·1M·99.9% up
  • TTogether$0.14 in·$0.28 out·1M·100% up
  • Alibaba Cloud$0.18 in·$0.53 out·1M·99.5% up
  • MMancerfp8$0.20 in·$0.60 out·1M·100% up
  • SSiliconFlowfp8$0.22 in·$0.66 out·1M·99.3% up
  • GGMI Cloudfp8$0.29 in·$0.86 out·1M·100% up
  • PPhala$0.31 in·$0.92 out·1M·100% up
  • NNovitafp8$0.41 in·$1.23 out·1M·100% up
  • AAtlasCloudfp4$0.44 in·$1.32 out·1M·99.9% up
  • Baidu Qianfanfp8$0.44 in·$1.32 out·1M·100% up
  • Cloudflare Workers AI$0.44 in·$1.32 out·1M·98.6% up

Per million tokens. Prices and uptime via OpenRouter, checked 10 Oct 2026.

Common questions

What is the difference between Claude Sonnet 4.5 and DeepSeek V4 Flash 0731?

Claude Sonnet 4.5 is developed by Anthropic while DeepSeek V4 Flash 0731 is developed by DeepSeek. Claude Sonnet 4.5 has a 200K token context window vs DeepSeek V4 Flash 0731's 1.0M. You can compare their actual outputs across 42 challenges on Rival to see how they differ in practice.

Which is better, Claude Sonnet 4.5 or DeepSeek V4 Flash 0731?

It depends on your use case. Claude Sonnet 4.5 and DeepSeek V4 Flash 0731 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.

How much does Claude Sonnet 4.5 cost compared to DeepSeek V4 Flash 0731?

Claude Sonnet 4.5 costs $3/M input tokens and DeepSeek V4 Flash 0731 costs $0.14/M input tokens. DeepSeek V4 Flash 0731 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.

How can I compare Claude Sonnet 4.5 and DeepSeek V4 Flash 0731 on Rival?

This page shows a side-by-side comparison of Claude Sonnet 4.5 and DeepSeek V4 Flash 0731 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.

More comparisons

Against the newest arrivals

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  • DeepSeek V4 Flash 0731 vs Claude Sonnet 5.5Landed Sep 2026
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  • DeepSeek V4 Flash 0731 vs Qwen3.8 Max PrimeLanded Sep 2026

Same lab, same size, long tail

  • Claude Sonnet 4.5 vs Claude Haiku 5.5Same lab
  • Claude Sonnet 4.5 vs Claude Sonnet 5.5Same lab
  • DeepSeek V4 Flash 0731 vs DeepSeek V4 Flash Vision ExpSame lab
  • DeepSeek V4 Flash 0731 vs DeepSeek V4.1 FlashSame lab
  • Claude Sonnet 4.5 vs Nex-N2.5-Mini (free)Same size
  • Claude Sonnet 4.5 vs Nex-N2.5-Pro (free)Same size
  • Claude Sonnet 4.5 vs North Mini CodeNew provider
  • DeepSeek V4 Flash 0731 vs Amazon Nova 2 LiteNew provider

Model pages

  • Claude Sonnet 4.543 outputs, specs and price
  • DeepSeek V4 Flash 073158 outputs, specs and price
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