Kimi K3.1 Pro vs Muse Spark Open
Kimi K3.1 Pro leads Muse Spark Open on coding, 82.2 to 47.3 on the Vibe Coding Index, and Muse Spark Open costs 2.4x less per output token ($4.25 vs $10.00 per million). Updated October 29, 2026; 25 benchmarks have a result for both.
Kimi K3.1 Pro or Muse Spark Open: which to pick
Pick Kimi K3.1 Pro for coding: it scores 82.2 on the Vibe Coding Index against 47.3 for Muse Spark Open.
Pick Muse Spark Open for output tokens 2.4x cheaper ($4.25 vs $10.00 per million) and work measured by LiveBench research or Tax Agent Bench (Vals AI), where it leads.
- Shared results
- 25
- Kimi K3.1 Pro only
- 10
- Muse Spark Open only
- 13
- Like-for-like categories
- 6 of 9
Only benchmarks that tested both models count toward a pick; a result only one model has is shown but not compared.
Which one for your work
Each card is decided by one number both models carry. Where only one has it, the card says so and makes no call.
Coding
Vibe Coding Index, six public coding benchmarks
Kimi K3.1 Pro
Kimi K3.1 Pro scores 82.2 against 47.3.
4 benchmarks behind each score
Intelligence
AA Intelligence Index
No call
Only Kimi K3.1 Pro has a AA Intelligence Index result, 46.0.
Directional only
Web design
Design Arena: websites
Kimi K3.1 Pro
Kimi K3.1 Pro leads, 1325 against 1306.
Same board, both measured
General
Vals Index
Kimi K3.1 Pro
Kimi K3.1 Pro leads, 62.5% against 48.6%.
Same board, both measured
Long documents
Listed context window
No call
Both take 1.05M tokens.
Listed by OpenRouter
Everyday cost
1K input + 500 output tokens
Muse Spark Open
Kimi K3.1 Pro $0.0070, Muse Spark Open $0.0034 per turn.
List prices
At a glance
- Coding index
- Kimi K3.1 Pro 82.2 from 4 benchmarks, Muse Spark Open 47.3 from 4 benchmarks.
- Widest category
- Math, 26.4 points apart on average over 1 shared benchmark.
- Widest single gap
- Terminal-Bench 4 (Vals AI): Kimi K3.1 Pro 63.6% against Muse Spark Open 6.6%, 76.1 points apart on a 0 to 100 scale.
- Output price
- Kimi K3.1 Pro $10.00 against Muse Spark Open $4.25 per million output tokens, 2.4x apart.
- Context window
- Both take 1.05M tokens.
Benchmark by benchmark
First the score: boards each model leads, per category, where both have a result. Then every board, a category to a fold; bars are each result on a 0 to 100 scale, so compare the two in a row, not one row with another.
| Category | Kimi K3.1 Pro | Bars | Muse Spark Open | Ties |
|---|---|---|---|---|
| Coding | 8 | 0 | ||
| Agentic work | 2 | 4 | ||
| Reasoning | 2 | 0 | ||
| Math | 1 | 0 | ||
| Web design | 5 | 0 | ||
| General | 3 | 0 | ||
| All shared boards | 21 | 4 |
CodingLike-for-likeSix of these boards feed the Vibe Coding Index80
| Benchmark | Kimi K3.1 Pro | Muse Spark Open | Leader |
|---|---|---|---|
| LiveBench coding | 81.8% | 73.6% | Kimi K3.1 Pro |
| LMArena WebDev | 1695 | 1526 | Kimi K3.1 Pro |
| Terminal-Bench 4 (Vals AI) | 63.6% | 6.6% | Kimi K3.1 Pro |
| Vibe Code Bench (Vals AI) | 84.9% | 76.2% | Kimi K3.1 Pro |
| Code migration (Vals AI) | Not measured | 21.2% | Only Muse Spark Open measured |
| IOI (Vals AI) | 81.9% | Not measured | Only Kimi K3.1 Pro measured |
| SciCode | 60.8% | 58.4% | Kimi K3.1 Pro |
| ALE-Bench | 1932.8 | 1590.1 | Kimi K3.1 Pro |
| LMArena WebDev: React | 1701 | 1524 | Kimi K3.1 Pro |
| LMArena WebDev: HTML | 1706 | 1481 | Kimi K3.1 Pro |
| SWE-Bench Pro V2 | Not measured | 95.0% | Only Muse Spark Open measured |
| Neither model has a result on the other 32 boards here | |||
IntelligenceDirectional onlyPublic boards, shown as published, kept out of the index2 boards, none shared
| Benchmark | Kimi K3.1 Pro | Muse Spark Open | Leader |
|---|---|---|---|
| AA Intelligence Index | 46.0 | Not measured | Only Kimi K3.1 Pro measured |
| Epoch Capabilities Index | Not measured | 155.1 | Only Muse Spark Open measured |
Agentic workLike-for-likePublic boards, shown as published, kept out of the index24
| Benchmark | Kimi K3.1 Pro | Muse Spark Open | Leader |
|---|---|---|---|
| LiveBench research | 77.9% | 80.3% | Muse Spark Open |
| LiveBench browser | 75.9% | 26.2% | Kimi K3.1 Pro |
| LiveBench long agentic | 39.1% | 11.7% | Kimi K3.1 Pro |
| Finance Agent (Vals AI) | Not measured | 61.3% | Only Muse Spark Open measured |
| Tax Agent Bench (Vals AI) | 24.9% | 26.3% | Muse Spark Open |
| Legal Research Bench (Vals AI) | 37.5% | 38.5% | Muse Spark Open |
| Harvey's Legal Agent Benchmark (Vals AI) | 11.7% | 25.0% | Muse Spark Open |
| Excel Modeling Benchmark (Vals AI) | Not measured | 53.7% | Only Muse Spark Open measured |
| BioMysteryBench (Vals AI) | 75.6% | Not measured | Only Kimi K3.1 Pro measured |
| Terminal-Bench-Science (Vals AI) | 31.4% | Not measured | Only Kimi K3.1 Pro measured |
| Vals Science Index | 44.4% | Not measured | Only Kimi K3.1 Pro measured |
| APEX-Agents | Not measured | 33.4% | Only Muse Spark Open measured |
| Neither model has a result on the other 30 boards here | |||
ReasoningLike-for-likePublic boards, shown as published, kept out of the index20
| Benchmark | Kimi K3.1 Pro | Muse Spark Open | Leader |
|---|---|---|---|
| LiveBench reasoning | 91.1% | 73.7% | Kimi K3.1 Pro |
| MysteryMechanism (Vals AI) | 26.1% | Not measured | Only Kimi K3.1 Pro measured |
| GPQA Diamond (Artificial Analysis run) | Not measured | 89.0% | Only Muse Spark Open measured |
| Humanity's Last Exam (Artificial Analysis run) | 52.5% | 43.9% | Kimi K3.1 Pro |
| ARC-AGI | Not measured | 89.0% | Only Muse Spark Open measured |
| ARC-AGI-2 | Not measured | 57.5% | Only Muse Spark Open measured |
| Humanity's Last Exam (Scale run) | Not measured | 28.0% | Only Muse Spark Open measured |
| Neither model has a result on the other 16 boards here | |||
MathLike-for-likePublic boards, shown as published, kept out of the index10
| Benchmark | Kimi K3.1 Pro | Muse Spark Open | Leader |
|---|---|---|---|
| ProofBench | 91.0% | Not measured | Only Kimi K3.1 Pro measured |
| MathArena | 59.6% | 33.1% | Kimi K3.1 Pro |
| Neither model has a result on the other 12 boards here | |||
KnowledgeDirectional onlyPublic boards, shown as published, kept out of the index1 board, none shared
| Benchmark | Kimi K3.1 Pro | Muse Spark Open | Leader |
|---|---|---|---|
| PRBench Legal | Not measured | 59.8% | Only Muse Spark Open measured |
| Neither model has a result on the other 19 boards here | |||
Web designLike-for-likePublic boards, shown as published, kept out of the index50
| Benchmark | Kimi K3.1 Pro | Muse Spark Open | Leader |
|---|---|---|---|
| Design Arena: websites | 1325 | 1306 | Kimi K3.1 Pro |
| Design Arena: UI components | 1400 | 1338 | Kimi K3.1 Pro |
| Design Arena: game dev | 1410 | 1272 | Kimi K3.1 Pro |
| Design Arena: data viz | 1300 | Not measured | Only Kimi K3.1 Pro measured |
| Design Arena: 3D | 1451 | Not measured | Only Kimi K3.1 Pro measured |
| Design Arena: all code categories | 1354 | 1301 | Kimi K3.1 Pro |
| Design Arena: SVG | 1328 | Not measured | Only Kimi K3.1 Pro measured |
| LiveBench design | 77.8% | 60.3% | Kimi K3.1 Pro |
| Neither model has a result on the other 1 board here | |||
GeneralLike-for-likePublic boards, shown as published, kept out of the index30
| Benchmark | Kimi K3.1 Pro | Muse Spark Open | Leader |
|---|---|---|---|
| Vals Index | 62.5% | 48.6% | Kimi K3.1 Pro |
| LiveBench data analysis | 79.1% | 60.2% | Kimi K3.1 Pro |
| SAGE (Vals AI) | Not measured | 85.8% | Only Muse Spark Open measured |
| Long context reasoning (AA-LCR) | 86.3% | 78.3% | Kimi K3.1 Pro |
| MultiChallenge | Not measured | 74.2% | Only Muse Spark Open measured |
| Neither model has a result on the other 43 boards here | |||
Image generationNot comparablePublic boards, shown as published, kept out of the index0 boards, none shared
| Benchmark | Kimi K3.1 Pro | Muse Spark Open | Leader |
|---|---|---|---|
| Neither model has a result on 5 boards here | |||
What each workload costs
Three fixed token mixes at each model's listed price, so per-token rates become a bill.
Chat turn
1K input + 500 output tokens
Muse Spark Open costs less
Repository review
50K input + 3K output tokens
Muse Spark Open costs less
Agent loop
200K input + 10K output tokens
Muse Spark Open costs less
Listed OpenRouter rates, without cache or batch discounts. A workload that does not fit a model's context window would need splitting.
Specification differences
The leading value in a row is marked; a row with a missing value names no leader. Our two rows are marked in red.
| Specification | MoonshotAI Kimi K3.1 Pro | Meta Muse Spark Open |
|---|---|---|
| Maker | Moonshot AI | Meta |
| Weights | No public weights listed | Open weights |
| Released | October 23, 2026 | October 15, 2026 |
| Context window | 1.05M | 1.05M |
| Input $/Mtok | $2.00 | $1.25 |
| Output $/Mtok | $10.00 | $4.25 |
| Coding index | 82.2 | 47.3 |
| Independent measurements behind it | 4 | 4 |
| Cost per solved task | Not computable | Not computable |
| Source | OpenRouter listing | OpenRouter listing |
Questions
Is Kimi K3.1 Pro better than Muse Spark Open for coding?
Pick Kimi K3.1 Pro for coding: it scores 82.2 on the Vibe Coding Index against 47.3 for Muse Spark Open. Pick Muse Spark Open for output tokens 2.4x cheaper ($4.25 vs $10.00 per million) and work measured by LiveBench research or Tax Agent Bench (Vals AI), where it leads.
Which is cheaper, Kimi K3.1 Pro or Muse Spark Open?
Kimi K3.1 Pro costs $2.00 per million input tokens and $10.00 per million output tokens; Muse Spark Open costs $1.25 and $4.25. Cost per solved task is known for neither of them.
Which has the bigger context window, Kimi K3.1 Pro or Muse Spark Open?
Neither: both take 1.05M tokens.
How many benchmarks is the Kimi K3.1 Pro vs Muse Spark Open comparison based on?
25 benchmarks have a result for both models as of October 29, 2026. Kimi K3.1 Pro's coding index rests on 4 independent benchmarks and Muse Spark Open's on 4. Where only one model has a result, the page says so instead of naming a winner.