Real head-to-head · same prompt, one shot
Grok vs Kimi K3
Snappy + real-time — the X-native model. vs Moonshot's 2.5T flagship — 1M context, tuned for long-horizon agent work.
Head-to-head verdict: Grok wins 25–18.
What I tested — same prompt, two models
I run the same fixed prompt set through every new model the day it drops — same string, one shot, single HTML file out — and I score the result 0–10 on whether it ran, how close it hit the brief, and how good it looked. Below is what came out when I gave the exact same prompts to Grok and Kimi K3, side by side, on 47 shared tasks inside the Agent Operating System.
Both models were given identical prompts inside the Agent Operating System — no help, no iteration, no "best of N" tricks. I run each prompt once, save the HTML file the model produces, and score it 0–10 on whether it ran, how close it hit the brief, and how good it looked. The scoring is mine. The verdicts below are pulled from my source comparison guides at agentos.guide where I publish every score and the reasoning behind it.
Grok · Used for real-time content workflows where the model needs current X timeline context. Standalone bench scoring pending.
Kimi K3 · Wired into the Agent OS as the `kimi-k3` Hermes profile and a K3 speed-toggle in the Kimi Code tab — used for long unattended agent runs where a slow-but-right model beats a fast-but-forgetful one.
Side-by-side on 50 shared tasks
Click any cell to play that model's actual one-shot attempt. Medals are derived from my 0–10 scores per task (highest = 🥇, second = 🥈, third = 🥉).
Task ↓
Grok
Kimi K3
Game
Game
Game
Game
Game
Game
Game
Game
Game
Game
Game
Game
Game
Game
Game
Game
Game
Game
Game
Game
Game
Game
Game
Page
Where Grok beat Kimi K3
The tasks where I gave Grok a higher 0–10 score on the same prompt — with the actual commentary from my source guides.
Twilightvale
Game
Grok 9.5
·
Kimi K3 1.0
(+8.5)
· winner · open world depth
What I saw: Twilight Vale — 3D open-world RPG with hand-crafted village, NPCs, combat, day/night, weather, inventory. 38KB — densest build of the bench, edges out Fusion's 32KB.
Doom
Game
Grok 8.5
·
Kimi K3 1.0
(+7.5)
What I saw: Doom-style FPS with sprite enemies, gun + muzzle flash + ammo/health HUD, textures, pointer-lock mouse-look. 22KB.
Dragonflight
Game
Grok 8.5
·
Kimi K3 1.0
(+7.5)
What I saw: Fly a dragon through neon rings with score + fire-breath + fury HUD. 28KB.
Neonblaster
Game
Grok 8.5
·
Kimi K3 1.0
(+7.5)
What I saw: Juicy 2D arcade space shooter — waves, bosses, power-ups, screen-shake, synth music via Web Audio, neon particles. 24KB.
Orbit
Sim
Grok 8.5
·
Kimi K3 1.0
(+7.5)
What I saw: A proper inner solar system now — a glowing Sun, four planets riding clean elliptical rings, a starfield, a data HUD and play/speed controls. The vague first sentence drew blurry circles; this one reads instantly.
Where Kimi K3 beat Grok
The tasks where I gave Kimi K3 a higher 0–10 score on the same prompt — with the actual commentary from my source guides.
Aurora
Visual
Kimi K3 8.7
·
Grok 7.0
(+1.7)
· volumetric 3D aurora
What I saw: Gorgeous flowing volumetric aurora ribbons with convincing fbm noise, layered mountains, spruce silhouettes, moon, stars and a shooting star make a genuinely atmospheric scene; the elegant typography, palette switcher and vignette give it a shippable polish that edges past the fi…
Matrix
Visual
Kimi K3 8.6
·
Grok 7.0
(+1.6)
· Interactive polished rain
What I saw: Screenshot shows crisp katakana glyph rain with bright leading heads fading trails, a glowing mouse-pulse orb, scanline/vignette CRT treatment and a strong glowing title — clearly on-brief and polished. Rich interactivity (6 themes, click bursts, mouse gusts, pause/fullscreen) an…
Fluid
Sim
Kimi K3 9.0
·
Grok 7.5
(+1.5)
What I saw: Gorgeous, textbook-quality WebGL fluid sim with rich swirling dye, added particle sparkle, and polished UI (gradient title, hint pill, control buttons) — the vorticity/pressure-solve pipeline and half-float fallback handling are all correct and shippable; only minor knock is the …
Boids
Sim
Kimi K3 8.6
·
Grok 7.5
(+1.1)
· 3D flocking birds
What I saw: Renders a polished 3D boids sim with genuine emergent flocking clusters, colorful instanced birds with wings, a glowing repel/attract orb, dusk gradient sky and a clean control panel — strong visual and simulation depth that matches the top of the field. Minor weakness: 44fps at …
Fractal
Sim
Kimi K3 8.6
·
Grok 7.5
(+1.1)
· GPU realtime explorer
What I saw: Crisp GPU-shader Mandelbrot renders beautifully with smooth continuous coloring, vivid Aurora palette, and a polished glassy HUD; full feature set (mode toggle, Julia spawn, palettes, zoom/pan, keyboard) makes it a task winner, only mild nit being the intense magenta background d…
Strengths & weaknesses I logged
Grok
Strengths
- Real-time access to X timeline data — unique signal no other model has
- Snappy latency on shorter prompts
- 256K context window keeps pace with the open-weights field
Trade-offs
- 13 demos on the bench but zero have curated 0–10 verdicts yet — currently unranked
- API access is gated behind X Premium, awkward for backend agent loops
Kimi K3
Strengths
- Launch-day benchmarks put it around the Fable/Sol tier, with Terminal Bench (agentic terminal-driving) the standout
- 1M-token context verified on this bench's needle test: exact recall from 162k tokens of noise in 18s
- One-shot builds run long but land complete — its first bench game (13.4 min of thinking, 30,880 tokens) playtested with zero JS errors
- Included in the Kimi coding plan — frontier tier without a new bill
Trade-offs
- Slow on hard tasks — early testers report up to ~35 minutes at max reasoning; this bench saw 13+ minute single builds
- Launch-day rate limits on OpenRouter (429s) — the coding-plan endpoint was the reliable route
- Self-reports as K2.7 if you ask it — verify the served model via the API response, not the model's word
Pricing & context — the spec sheet
| Spec | Grok | Kimi K3 |
|---|---|---|
| Vendor | xAI | Moonshot AI |
| Context window | 256,000 tokens | 1,048,576 tokens — a full codebase in working memory |
| Price | Subscription via X Premium | $3 / M in |
| Pricing detail | Bundled with X (Twitter) Premium subscription — no per-token bill for end users, no individual API pricing for the chat product. | Launched July 16, 2026. 2.5T-param MoE. $3/M input on OpenRouter at launch; included at no extra cost in the Kimi coding plan (`k3` on the coding endpoint). |
| Release | 2026-04 | 2026-07-16 |
| Bench coverage | 43/47 scored · avg 8.09/10 | 50/50 scored · avg 5.81/10 |
The verdict — which should you pick?
Across 43 scored shared tasks, Grok averaged 8.09/10, beating Kimi K3's 5.76/10 by 2.33 points. Pick Grok when the build has to ship on the first prompt and you can afford the trade-offs in the comparison below.
If you only run one of these inside your stack, the head-to-head average above is the call. If you can run both, my honest play is to wire Grok and Kimi K3 both into the Agent Operating System and dispatch each from the kanban by task type — workflows that need live x / twitter context → Grok, long-horizon agent runs → Kimi K3. That's the same setup I run for the 4,000+ founders inside the AI Profit Boardroom.
FAQ — Grok vs Kimi K3
Which is better, Grok or Kimi K3?
On Goldie Bench, Grok averages 8.09/10 across the shared tasks, with 5 gold, 2 silver, 7 bronze overall. Kimi K3 averages 5.76/10, with 9 gold, 5 silver, 7 bronze. Grok wins the head-to-head 25–18.
How much does Grok cost vs Kimi K3?
Grok: Bundled with X (Twitter) Premium subscription — no per-token bill for end users, no individual API pricing for the chat product. Kimi K3: Launched July 16, 2026. 2.5T-param MoE. $3/M input on OpenRouter at launch; included at no extra cost in the Kimi coding plan (`k3` on the coding endpoint).
What's the context window for Grok vs Kimi K3?
Grok has a 256,000 tokens context window. Kimi K3 has a 1,048,576 tokens — a full codebase in working memory context window.
When should I pick Grok over Kimi K3?
Pick Grok for: Workflows that need live X / Twitter context; Snappy prompts where latency matters; Researchers comparing X-native models against the rest of the field. The trade-off is the weaknesses we logged on the bench: 13 demos on the bench but zero have curated 0–10 verdicts yet — currently unranked; API access is gated behind X Premium, awkward for backend agent loops.
When should I pick Kimi K3 over Grok?
Pick Kimi K3 for: long-horizon agent runs; whole-repo context work; terminal-driving agents. The trade-off is the weaknesses we logged on the bench: Slow on hard tasks — early testers report up to ~35 minutes at max reasoning; this bench saw 13+ minute single builds; Launch-day rate limits on OpenRouter (429s) — the coding-plan endpoint was the reliable route; Self-reports as K2.7 if you ask it — verify the served model via the API response, not the model's word.
How does Goldie Bench score Grok vs Kimi K3?
Every demo on this page was built by Julian Goldie inside the Agent Operating System — same fixed prompt for both models, one shot, single HTML file out. Each result gets a 0–10 score on whether it ran, how close it hit the brief, and how good it looked. The highest score on each task gets gold; second gets silver; third gets bronze. See methodology for full provenance.
Related comparisons
Other head-to-heads using the same scoring system:
Grok vs Fusion Kimi K3 vs Fusion Grok vs Hermes MoA Kimi K3 vs Hermes MoA Grok vs GPT-5.6 Sol Kimi K3 vs GPT-5.6 Sol Grok vs Claude Fable 5 Kimi K3 vs Claude Fable 5Full model pages: Grok · Kimi K3 · back to the leaderboard
The same stack Julian uses
Run this stack yourself.
Every demo on this bench was built inside the Agent Operating System — one prompt, one shot, single HTML file out. The Agent OS, the prompts, the templates, the weekly walkthroughs and 4,000+ founders shipping with it every day all live inside the AI Profit Boardroom.
4,000+founders
258documented wins
38countries
$59/momonthly