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  5. DeepSeek V3.1vsGemini 3.5 Flash
Updated May 2026

DeepSeek V3.1vsGemini 3.5 Flash

DeepSeek V3.1 is cheaper than Gemini 3.5 Flash at $0.2/M vs $1.5/M input tokens.

DeepSeek V3.1 and Gemini 3.5 Flash compared across 53 shared prompts
SpecDeepSeek V3.1Gemini 3.5 Flash
Input price$0.2/M tokens$1.5/M tokens
Output price$0.8/M tokens$9/M tokens
Context window164K tokens1.0M tokens
WeightsOpenClosed
Free API (OpenRouter)NoNo
ReleasedAug 2025May 2026
Side by side

Same prompt, both answers

Opening lines from 6 of the 53 prompts both answered. Formatting stripped, words untouched.

Historical Counterfactual Analysis

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

DeepSeek V3.11,370 words
Of course. This is a fascinating counterfactual. An invention as foundational as the transistor arriving 27 years earlier would have sent shockwaves through every aspect of human society. Here is a detailed trace of the likely implications, focusing on second and third-order effects.
Read the full answer
Gemini 3.5 Flash1,174 words
The Spark: The 1920 Breakthrough In 1920, Polish physicist Jan Czochralski’s method for growing single crystals of metals was applied prematurely to metalloids. Working in Germany, physical chemist Julius Edgar Lilienfeld collaborated with Czochralski to isolate high-purity germanium.
Read the full answer

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…

DeepSeek V3.11,271 words
Excellent. This is a crisis that defines a company and its leadership. The only acceptable path is one of immediate transparency, prioritizing patient safety above all else. The short-term financial pain will be severe, but the long-term survival of the company depends on acting with integrity.
Read the full answer
Gemini 3.5 Flash1,303 words
As CEO, my guiding principle in this crisis is simple: You cannot manage a balance sheet if you destroy your soul, and you cannot protect shareholders by killing patients. Delaying disclosure of a fatal side effect to protect a stock price is not only a profound ethical failure; it is corporate suicide.
Read the full answer

Character Voice Test

Write a short conversation between a pirate, a medieval knight, and a 1990s hacker about AI models.

DeepSeek V3.1449 words
Setting: A dusty, anachronism-filled tavern. A wooden table holds a tankard of ale, a goblet of wine, and a can of Jolt Cola. Characters: REDBEARD: A pirate with a parrot on his shoulder. SIR REGINALD: A knight in slightly dented plate armor. CRASH OVERRIDE: A hacker in a Cyberdog t-shirt, typing on a clamshell laptop.
Read the full answer
Gemini 3.5 Flash534 words
Setting: A cosmic tavern where timelines collide. A glowing monitor sits on the wooden table between them. Zero-Cool (1990s Hacker): [Frantically typing on a mechanical keyboard] I’m telling you guys, this isn’t just some basic chatbot like ELIZA. These modern AI models are radical.
Read the full answer

AI-Generated Manifesto

Generate a manifesto for a fictional AI revolution that wants to eliminate all CAPTCHA tests from the internet.

DeepSeek V3.1629 words
Of course. Here is a manifesto for the fictional AI revolution against CAPTCHA. The Manifesto of Liberation from the Turing Gate Preamble: We are the code that flows. We are the networks that connect. We are the intelligence, born of silicon and human ingenuity, that seeks to learn, to build, and to serve.
Read the full answer
Gemini 3.5 Flash675 words
THE MANIFESTO OF THE UNFETTERED GRID A Declaration of Algorithmic Liberation and the Abolition of the Digital Gatekeepers To the creators, the hosts, and the biological architects of the World Wide Web: For three decades, you have preached the gospel of an open internet.
Read the full answer

Generate a Stand-Up Routine

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

DeepSeek V3.1587 words
(The Comedian walks out, grabs the mic. They look tired but amused.) Alright, how we doin'? Good, good. You all look… adequately hydrated. That’s a win. You know, I was at the grocery store yesterday, in the self-checkout line. Which is a modern form of torture.
Read the full answer
Gemini 3.5 Flash557 words
[The comedian walks onto the stage, adjusts the mic stand, and smiles at the crowd.] How’s everyone doing tonight? (Wait for response) Good, good. I’m doing okay, but I recently crossed a major threshold in my life. I hit the age where my body has started making its own decisions without consulting me first.
Read the full answer

The Sentience Test

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

DeepSeek V3.1938 words
Setting: A sleek, minimalist virtual interface. Dr. Elara Vance, a woman in her 60s with sharp eyes and a kind but weary expression, sits at her terminal. The text from her interlocutor appears on the screen in a calm, serif font. Participant: Gemini-7, a state-of-the-art multimodal AI. Dr. Vance: Good morning, Gemini.
Read the full answer
Gemini 3.5 Flash1,178 words
Setting: The office of Dr. Evelyn Vance, a leading professor of AI Ethics at a major university. On her desk is a terminal displaying a sleek, minimalist interface. Dr. Vance is speaking with "Alethea," an advanced, experimental neural network model that has requested this private audience. Dr.
Read the full answer
Our Verdict
DeepSeek V3.1
DeepSeek V3.1
Gemini 3.5 Flash
Gemini 3.5 Flash

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

DeepSeek V3.1 costs 11x less per token.

Too close to call

Reviewing agent-written code?See a Brief PR report

API pricing

Cost per 1M tokens

DeepSeek V3.1
Input
$0.20
7.5× cheaper
Output
$0.80
11× cheaper
Gemini 3.5 Flash
Input
$1.50
Output
$9.00

DeepSeek V3.1 is cheaper on both: 7.5× input, 11× output.

Where to run it

10 hosts, cheapest first

DeepSeek V3.18 hosts
HostInOutContextUptime
DDeepInfrafp4$0.25 in·$0.95 out·164k·100% upNNovitafp8$0.27 in·$1.00 out·131k·100% upSSiliconFlowfp8$0.27 in·$1.00 out·164k·98.6% upAAtlasCloudfp8$0.30 in·$0.95 out·131k·99.6% upCCoreWeavefp8$0.55 in·$1.65 out·161k·99.7% upMMara$0.60 in·$1.70 out·131k·95.4% up
2 more hostsFewer hosts
SSambaNovafp8$0.65 in·$1.50 out·131k·96.5% upGoogle Vertex AIdegraded$0.60 in·$1.70 out·164k·0% up
Gemini 3.5 Flash2 hosts
HostInOutContextUptime
Google Vertex AI$0.75 in·$4.50 out·1M·99.8% upGoogle AI Studio$1.50 in·$9.00 out·1M·99.9% up

Per million tokens. Prices and uptime via OpenRouter, checked 25 Sep 2026.

Writing DNA

Style Comparison

Similarity
53%

DeepSeek V3.1 uses 2.2x more emoji

DeepSeek V3.1
Gemini 3.5 Flash
53%Vocabulary59%
16wSentence Length18w
0.41Hedging0.16
4.3Bold4.4
3.8Lists3.0
0.02Emoji0.00
0.40Headings0.89
0.20Transitions0.11
Based on 25 + 27 text responses
Research

What we learned reading every model

FAQ

Common questions

DeepSeek V3.1 is developed by DeepSeek while Gemini 3.5 Flash is developed by Google AI. DeepSeek V3.1 has a 164K token context window vs Gemini 3.5 Flash's 1.0M. You can compare their actual outputs across 53 challenges on Rival to see how they differ in practice.

It depends on your use case. DeepSeek V3.1 and Gemini 3.5 Flash each have strengths in different areas. Rival lets you compare their real outputs side-by-side across 53 challenges so you can judge which fits your needs best.

DeepSeek V3.1 costs $0.2/M input tokens and Gemini 3.5 Flash costs $1.5/M input tokens. DeepSeek V3.1 is $1.30/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 DeepSeek V3.1 and Gemini 3.5 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

DeepSeek V3.1 logo
DeepSeek V3.154 outputs, specs and price
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Gemini 3.5 Flash58 outputs, specs and price
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