Muse Spark Open vs Solar Mini 4
Solar Mini 4 costs 21.3x less per output token than Muse Spark Open ($0.20 vs $4.25 per million). Updated October 22, 2026; 5 benchmarks have a result for both.
Muse Spark Open or Solar Mini 4: which to pick
Only Muse Spark Open has a coding score, 47.4 on the Vibe Coding Index; Solar Mini 4 has none, so the two cannot be ranked on coding.
Pick Solar Mini 4 for output tokens 21.3x cheaper ($0.20 vs $4.25 per million) and work measured by Long context reasoning (AA-LCR), where it leads.
- Shared results
- 5
- Muse Spark Open only
- 23
- Solar Mini 4 only
- 2
- Like-for-like categories
- 4 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
No call
Only Muse Spark Open has a coding score, so no call is made.
One side not measured
Intelligence
AA Intelligence Index
No call
Only Solar Mini 4 has a AA Intelligence Index result, 24.1.
Directional only
Web design
Design Arena: websites
Muse Spark Open
Muse Spark Open leads, 1310 against 1158.
Same board, both measured
General
Vals Index
No call
Only Muse Spark Open has a Vals Index result, 48.6%.
Directional only
Long documents
Listed context window
Muse Spark Open
Muse Spark Open takes 1.05M tokens against 524K.
Listed by OpenRouter
Everyday cost
1K input + 500 output tokens
Solar Mini 4
Muse Spark Open $0.0034, Solar Mini 4 $0.0001 per turn.
List prices
At a glance
- Coding index
- Muse Spark Open 47.4 from 4 benchmarks, Solar Mini 4 not benchmarked.
- Widest category
- Web design, 20.5 points apart on average over 2 shared benchmarks.
- Widest single gap
- Design Arena: game dev: Muse Spark Open 1282 against Solar Mini 4 1106, 22.0 points apart on a 0 to 100 scale.
- Output price
- Muse Spark Open $4.25 against Solar Mini 4 $0.20 per million output tokens, 21.3x apart.
- Context window
- Muse Spark Open takes 1.05M tokens, Solar Mini 4 524K.
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 | Muse Spark Open | Bars | Solar Mini 4 | Ties |
|---|---|---|---|---|
| Coding | 1 | 0 | ||
| Reasoning | 1 | 0 | ||
| Web design | 2 | 0 | ||
| General | 0 | 1 | ||
| All shared boards | 4 | 1 |
CodingLike-for-likeSix of these boards feed the Vibe Coding Index10
| Benchmark | Muse Spark Open | Solar Mini 4 | Leader |
|---|---|---|---|
| LiveBench coding | 73.6% | Not measured | Only Muse Spark Open measured |
| LMArena WebDev | 1528 | Not measured | Only Muse Spark Open measured |
| Terminal-Bench 4 (Vals AI) | 6.6% | Not measured | Only Muse Spark Open measured |
| Vibe Code Bench (Vals AI) | 76.2% | Not measured | Only Muse Spark Open measured |
| Code migration (Vals AI) | 21.2% | Not measured | Only Muse Spark Open measured |
| SciCode | 58.4% | 47.6% | Muse Spark Open |
| ALE-Bench | 1590.1 | Not measured | Only Muse Spark Open measured |
| LMArena WebDev: React | 1529 | Not measured | Only Muse Spark Open measured |
| LMArena WebDev: HTML | 1495 | Not measured | Only Muse Spark Open measured |
| Neither model has a result on the other 30 boards here | |||
IntelligenceDirectional onlyPublic boards, shown as published, kept out of the index2 boards, none shared
| Benchmark | Muse Spark Open | Solar Mini 4 | Leader |
|---|---|---|---|
| AA Intelligence Index | Not measured | 24.1 | Only Solar Mini 4 measured |
| Epoch Capabilities Index | 155.1 | Not measured | Only Muse Spark Open measured |
Agentic workDirectional onlyPublic boards, shown as published, kept out of the index9 boards, none shared
| Benchmark | Muse Spark Open | Solar Mini 4 | Leader |
|---|---|---|---|
| LiveBench research | 80.3% | Not measured | Only Muse Spark Open measured |
| LiveBench browser | 36.0% | Not measured | Only Muse Spark Open measured |
| LiveBench long agentic | 18.9% | Not measured | Only Muse Spark Open measured |
| Finance Agent (Vals AI) | 61.3% | Not measured | Only Muse Spark Open measured |
| Tax Agent Bench (Vals AI) | 26.3% | Not measured | Only Muse Spark Open measured |
| Legal Research Bench (Vals AI) | 38.5% | Not measured | Only Muse Spark Open measured |
| Harvey's Legal Agent Benchmark (Vals AI) | 25.0% | Not measured | Only Muse Spark Open measured |
| Excel Modeling Benchmark (Vals AI) | 53.7% | Not measured | Only Muse Spark Open measured |
| APEX-Agents | 33.4% | Not measured | Only Muse Spark Open measured |
| Neither model has a result on the other 32 boards here | |||
ReasoningLike-for-likePublic boards, shown as published, kept out of the index10
| Benchmark | Muse Spark Open | Solar Mini 4 | Leader |
|---|---|---|---|
| LiveBench reasoning | 73.7% | Not measured | Only Muse Spark Open measured |
| GPQA Diamond (Artificial Analysis run) | 89.0% | Not measured | Only Muse Spark Open measured |
| Humanity's Last Exam (Artificial Analysis run) | 43.9% | 25.8% | Muse Spark Open |
| Neither model has a result on the other 19 boards here | |||
MathNot comparablePublic boards, shown as published, kept out of the index0 boards, none shared
| Benchmark | Muse Spark Open | Solar Mini 4 | Leader |
|---|---|---|---|
| Neither model has a result on 13 boards here | |||
KnowledgeNot comparablePublic boards, shown as published, kept out of the index0 boards, none shared
| Benchmark | Muse Spark Open | Solar Mini 4 | Leader |
|---|---|---|---|
| Neither model has a result on 18 boards here | |||
Web designLike-for-likePublic boards, shown as published, kept out of the index20
| Benchmark | Muse Spark Open | Solar Mini 4 | Leader |
|---|---|---|---|
| Design Arena: websites | 1310 | 1158 | Muse Spark Open |
| Design Arena: game dev | 1282 | 1106 | Muse Spark Open |
| Design Arena: all code categories | Not measured | 1150 | Only Solar Mini 4 measured |
| LiveBench design | 60.3% | Not measured | Only Muse Spark Open measured |
| Neither model has a result on the other 5 boards here | |||
GeneralLike-for-likePublic boards, shown as published, kept out of the index01
| Benchmark | Muse Spark Open | Solar Mini 4 | Leader |
|---|---|---|---|
| Vals Index | 48.6% | Not measured | Only Muse Spark Open measured |
| LiveBench data analysis | 60.2% | Not measured | Only Muse Spark Open measured |
| Long context reasoning (AA-LCR) | 78.3% | 83.3% | Solar Mini 4 |
| 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 | Muse Spark Open | Solar Mini 4 | 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
Solar Mini 4 costs less
Repository review
50K input + 3K output tokens
Solar Mini 4 costs less
Agent loop
200K input + 10K output tokens
Solar Mini 4 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 | Meta Muse Spark Open | Upstage Solar Mini 4 |
|---|---|---|
| Maker | Meta | Upstage |
| Weights | Open weights | No public weights listed |
| Released | October 15, 2026 | September 23, 2026 |
| Context window | 1.05M | 524K |
| Input $/Mtok | $1.25 | $0.05 |
| Output $/Mtok | $4.25 | $0.20 |
| Coding index | 47.4 | Not benchmarked |
| Independent measurements behind it | 4 | 0 |
| Cost per solved task | Not computable | Not computable |
| Source | OpenRouter listing | OpenRouter listing |
Questions
Is Muse Spark Open better than Solar Mini 4 for coding?
Only Muse Spark Open has a coding score, 47.4 on the Vibe Coding Index; Solar Mini 4 has none, so the two cannot be ranked on coding. Pick Solar Mini 4 for output tokens 21.3x cheaper ($0.20 vs $4.25 per million) and work measured by Long context reasoning (AA-LCR), where it leads.
Which is cheaper, Muse Spark Open or Solar Mini 4?
Muse Spark Open costs $1.25 per million input tokens and $4.25 per million output tokens; Solar Mini 4 costs $0.05 and $0.20. Cost per solved task is known for neither of them.
Which has the bigger context window, Muse Spark Open or Solar Mini 4?
Muse Spark Open, with 1.05M tokens against 524K.
How many benchmarks is the Muse Spark Open vs Solar Mini 4 comparison based on?
5 benchmarks have a result for both models as of October 22, 2026. Muse Spark Open's coding index rests on 4 independent benchmarks and Solar Mini 4's on 0. Where only one model has a result, the page says so instead of naming a winner.