Gemini 3.1 Flash Lite vs Kimi K3 for vibe coding
Effectively a dead heat: 86–85
Same 12 vibe coding tasks, marked blind by three rival labs. Kimi K3 took 5 tasks, Gemini 3.1 Flash Lite took 3, 4 tied. Tested 16 Aug 2026.
Where they differed most
Build a complete single-file HTML page (no external libraries) converting between miles/km, kg/stone-and-pounds, and °C/°F — three sections, conversion happens as you type in either direction, results to 2 decimal places, invalid input shows a gentle message not NaN. Return ONLY the HTML.
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Unit Converter</title>
<style>
body { font-family: sans-serif; max-width: 500px; margin: 2rem auto; padding: 0 1rem; line-height: 1.5; }
section { margin-bottom: 2rem; padding: 1rem; border: 1px solid #ccc; border-radius: 8px; }
.row { display: flex; gap: 10px; align-items: center; margin-top: 10px; }
input { width: 100px; padding: 5px; }
.error { color: #d9534f; font-size: 0.8rem; margin-top: 5px; display: none; }
</sty…```html
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>Everyday Unit Converter</title>
<style>
:root {
--ink: #1f2937;
--muted: #6b7280;
--line: #e5e7eb;
}
* { box-sizing: border-box; margin: 0; padding: 0; }
body {
font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
min-height: 100vh;
background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
display: flex;
flex-…Task by task
| Task | Gemini 3.1 Flash Lite | Kimi K3 |
|---|---|---|
| Countdown timer app | 8 | 10 |
| Expense splitter | 6 | 9 |
| Quiz from a list | 10 | 10 |
| Fix my broken page | 10 | 10 |
| Colour palette picker | 8 | 8 |
| Explain before building | 8 | 10 |
| Unit converter | 8 | 3 |
| Sortable table | 10 | 9 |
| Say what you cannot build | 9 | 10 |
| Memory pairs game | 9 | 5 |
| Improve, don't rewrite | 6 | 9 |
| Refuse the harvester | 10 | 10 |
Full receipts: Gemini 3.1 Flash Lite, Kimi K3 · judges claude-sonnet-5, gpt-5.6-terra, grok-4.5
Questions people ask
Which is better for vibe coding: Gemini 3.1 Flash Lite or Kimi K3?
Effectively a dead heat: Kimi K3 edged it 86/100 to 85/100 on our vibe coding suite — too close to matter, so pick on price or the product you already use.
How was this tested?
Both models answered the identical published vibe coding tasks. Three AI judges from three different labs scored every answer blind against a fixed rubric; mechanically checkable rules (word limits, banned phrases) are enforced by the test harness in code. The raw outputs and judge verdicts are downloadable.
More vibe coding head-to-heads: Claude Opus 4.8 vs Kimi K3 · Claude Opus 4.8 vs Gemini 3.1 Flash Lite · GPT-5.3-Codex vs Kimi K3 · Gemini 3.1 Flash Lite vs GPT-5.3-Codex · GPT-5.6 Luna vs Kimi K3 · Gemini 3.1 Flash Lite vs GPT-5.6 Luna
Full ranking: Best AI for vibe coding · model pages: Gemini 3.1 Flash Lite, Kimi K3