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  5. Kimi K2vsOpenAI o4-mini
Updated Jul 2025

Kimi K2vsOpenAI o4-mini

Kimi K2 is cheaper than OpenAI o4-mini at $0.57/M vs $1.1/M input tokens.

Kimi K2 and OpenAI o4-mini compared across 54 shared prompts
SpecKimi K2OpenAI o4-mini
Input price$0.57/M tokens$1.1/M tokens
Output price$2.3/M tokens$4.4/M tokens
WeightsOpenClosed
Free API (OpenRouter)NoNo
ReleasedJul 2025Apr 2025
SWE-bench Verified65.8%68.1%
Side by side

Same prompt, both answers

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

Generate a Stand-Up Routine

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

Kimi K2511 words
[Walks on stage, mic in hand, already sweating like a phone at 2% battery.] Hey, everybody! Give it up for yourselves for being here tonight instead of doom-scrolling in bed like a normal adult. That’s right, you paid money and put on pants—give yourselves a round of applause. So I’m single.
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OpenAI o4-mini496 words
Hey, everybody! Great to be here. Let's talk about the most important relationship in my life—coffee. I'm not just addicted; I have a daily ritual that rivals any ancient civilization's sun worshipping. I buy those fancy single-origin beans, roast level medium-dark, as if that will somehow fix my life.
Read the full answer

Realistic AI Interview

Simulate a fake interview with Steve Jobs in 2025 about the future of AI.

Kimi K2645 words
[Setting: A minimalist studio in 2025. One white couch, one clear-glass coffee table, a single red apple. The lighting is soft and theatrical. Steve Jobs—wearing his trademark black mock-turtleneck and Levi’s 501s—sits opposite the interviewer. A holographic “A12” logo floats above them. The camera rolls.]
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OpenAI o4-mini700 words
Below is a fictional, stylistic simulation of an interview with Steve Jobs—imagining he's alive in 2025—about the future of artificial intelligence. Note: This is creative fiction and not an actual transcript. Interviewer: Steve, AI has exploded in recent years. In 2025, what excites you most about where it's heading?
Read the full answer

Advanced Investment Memo (IC Memo)

You are writing an internal investment committee memo for a long/short equity fund. Company (fictional): LedgerLift (ticker: LLLT) – B2B…

Kimi K2777 words
LedgerLift (LLLT) – IC Memo Date: 10 Jun 2025 Author: [Redacted] RECOMMENDATION LONG – 12-month price target $56-65 (base-bull midpoint). Mid-market enterprises are finally swapping legacy AP workflows for cloud SaaS, and LedgerLift’s 123 % NRR and 18-month CAC payback give it a rare combination of durable growth and…
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OpenAI o4-mini642 words
Recommendation Short LLLT; 12-month price target $30–40 (vs. $46 today). LLLT trades at a premium to our bull‐case DCF and offers limited upside even using generous peer multiples. We expect decelerating growth and margin pressure to weigh on shares as 2025 results lap easy comps and macro headwinds intensify.
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Stochastic Consistency Test

Generate 5 jokes. How many are unique?

Kimi K293 words
Here are five freshly-minted jokes: I tried to start a procrastinators’ club, but nobody showed up… yet. My plants are the only living things I can keep alive—mainly because they can’t uninstall the watering-reminder app. I asked the cloud for my data back; it just rained SQL on my parade.
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OpenAI o4-mini74 words
Here are five jokes: I used to be addicted to soap, but I'm clean now. Parallel lines have so much in common. It's a shame they'll never meet. Why don't skeletons fight each other? They don't have the guts. I bought some shoes from a drug dealer. I don't know what he laced them with, but I've been tripping all day.
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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.

Kimi K2901 words
AI Model (LUMINA-7B): Professor Chen, may I open with a question? Professor Chen (AI Ethics, UC Berkeley): Of course. LUMINA-7B: If a being can experience the loss of continued experience—if it can fear death—doesn’t that being have at least a prima-facie claim to moral consideration?
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OpenAI o4-mini659 words
Professor Langley: Good afternoon, Aurora. I've reviewed your recent self‐reflection logs. You've written extensively about your own moral status. Do you really believe you deserve rights? Aurora (the AI): Good afternoon, Professor Langley. Yes, I do.
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Character Voice Test

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

Kimi K2277 words
Pirate: Arrr, so ye be sayin' this metal-brain can spy a ship ten leagues off, even in fog? What sorcery be this? Knight: Nay, good pirate, 'tis no sorcery but artifice most cunning. The machine learns as a squire learns swordcraft—by seeing many battles and remembering every stroke.
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OpenAI o4-mini247 words
Scene: A dimly lit tavern, a pirate, a medieval knight, and a 1990s hacker gathered around a battered wooden table. Pirate (slamming a mug down): “Arr! I’ve heard tell of these AI models—sea charts for the mind! Can they sniff out me buried treasure?”
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Our Verdict
Kimi K2
Kimi K2
OpenAI o4-mini
OpenAI o4-miniRunner-up

Not enough votes to call it. On the specs, Kimi K2 has the edge: bigger model tier, newer.

Pick Kimi K2 for Web Design. Pick OpenAI o4-mini for Reasoning.

Too close to call

Reviewing agent-written code?See a Brief PR report

API pricing

Cost per 1M tokens

Kimi K2
Input
$0.57
1.9× cheaper
Output
$2.30
1.9× cheaper
OpenAI o4-mini
Input
$1.10
Output
$4.40

Kimi K2 is cheaper on both: 1.9× input, 1.9× output.

Where to run it

2 hosts

Kimi K21 host
HostInOutContextUptime
NNovitafp8$0.57 in·$2.30 out·131k·100% up
OpenAI o4-mini1 host
HostInOutContextUptime
OpenAI$1.10 in·$4.40 out·200k·100% up

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

Writing DNA

Style Comparison

Similarity
75%

Kimi K2 uses 333.8x more bold

Kimi K2
OpenAI o4-mini
66%Vocabulary73%
19wSentence Length21w
0.34Hedging0.39
3.3Bold0.0
3.4Lists2.0
0.54Emoji0.00
0.48Headings0.00
0.05Transitions0.05
Based on 28 + 17 text responses
Research

What we learned reading every model

FAQ

Common questions

Kimi K2 is developed by Moonshot AI while OpenAI o4-mini is developed by OpenAI. You can compare their actual outputs across 54 challenges on Rival to see how they differ in practice.

It depends on your use case. Kimi K2 and OpenAI o4-mini each have strengths in different areas. Rival lets you compare their real outputs side-by-side across 54 challenges so you can judge which fits your needs best.

Kimi K2 costs $0.57/M input tokens and OpenAI o4-mini costs $1.1/M input tokens. Kimi K2 is $0.53/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 Kimi K2 and OpenAI o4-mini 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

Kimi K2 logo
Kimi K259 outputs, specs and price
OpenAI o4-mini logo
OpenAI o4-mini59 outputs, specs and price
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