Muse Spark Open vs Hy4 preview
Updated October 21, 2026. 10 benchmarks have a result for both. Coding is ranked on the Vibe Coding Index; every other board is shown as published.
Decision reading
Muse Spark Open and Hy4 preview are level for coding, 62.1 against 61.6 on the Vibe Coding Index, so price and context decide.
Pick Hy4 preview when output tokens cost 1.7x less, or when what matters is LMArena WebDev or Terminal-Bench 4 (Vals AI), where it leads. Pick Muse Spark Open when the benchmark that matters is Finance Agent (Vals AI), where it leads.
- Shared results
- 10
- Muse Spark Open only
- 16
- Hy4 preview only
- 14
- Like-for-like categories
- 2 of 9
Shared results can support a head-to-head reading. Results only one model has describe coverage, not superiority.
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, four public coding benchmarks
No call
Level: 62.1 against 61.6, inside 2 points.
2 and 1 benchmarks behind the scores
Web design
Design Arena: websites
No call
Only Muse Spark Open has a Design Arena: websites result, 1311.
Directional only
General
Vals Index
No call
Only Hy4 preview has a Vals Index result, 53.2%.
Directional only
Long documents
Listed context window
No call
Both take 1.05M tokens.
Listed by OpenRouter
Everyday cost
1K input + 500 output tokens
Hy4 preview
Muse Spark Open $0.0034, Hy4 preview $0.0021 per turn.
List prices
At a glance
- Coding index
- Muse Spark Open 62.1 from 2 benchmarks, Hy4 preview 61.6 from 1 benchmark.
- Widest category
- Coding, 12.2 points apart on average over 6 shared benchmarks.
- Widest single gap
- Code migration (Vals AI): Muse Spark Open 21.2% against Hy4 preview 47.4%, 26.3 points apart on a 0 to 100 scale.
- Output price
- Muse Spark Open $4.25 against Hy4 preview $2.501 per million output tokens, 1.7x 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 | Muse Spark Open | Bars | Hy4 preview | Ties |
|---|---|---|---|---|
| Coding | 0 | 6 | ||
| Agentic work | 1 | 3 | ||
| All shared boards | 1 | 9 |
CodingLike-for-likeFour of these boards feed the Vibe Coding Index06
| Benchmark | Muse Spark Open | Hy4 preview | Leader |
|---|---|---|---|
| LiveBench coding | 73.6% | Not measured | Only Muse Spark Open measured |
| LMArena WebDev | 1528 | 1631 | Hy4 preview |
| Terminal-Bench 4 (Vals AI) | 6.6% | 8.1% | Hy4 preview |
| Vibe Code Bench (Vals AI) | 76.2% | 77.5% | Hy4 preview |
| Code migration (Vals AI) | 21.2% | 47.4% | Hy4 preview |
| ProgramBench (Vals AI) | Not measured | 0.0% | Only Hy4 preview measured |
| IOI (Vals AI) | Not measured | 59.3% | Only Hy4 preview measured |
| Terminal-Bench 2.1 (Vals AI) | Not measured | 55.1% | Only Hy4 preview measured |
| CyberBench (Vals AI) | Not measured | 65.4% | Only Hy4 preview measured |
| SciCode | 58.4% | Not measured | Only Muse Spark Open measured |
| ALE-Bench | 1590.1 | Not measured | Only Muse Spark Open measured |
| LMArena WebDev: React | 1529 | 1653 | Hy4 preview |
| LMArena WebDev: HTML | 1495 | 1620 | Hy4 preview |
| Neither model has a result on the other 25 boards here | |||
IntelligenceDirectional onlyPublic boards, shown as published, kept out of the index1 board, none shared
| Benchmark | Muse Spark Open | Hy4 preview | Leader |
|---|---|---|---|
| Epoch Capabilities Index | 155.1 | Not measured | Only Muse Spark Open measured |
| Neither model has a result on the other 1 board here | |||
Agentic workLike-for-likePublic boards, shown as published, kept out of the index13
| Benchmark | Muse Spark Open | Hy4 preview | 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 |
| SREBench (Vals AI) | Not measured | 2.3% | Only Hy4 preview measured |
| Finance Agent (Vals AI) | 61.3% | 55.1% | Muse Spark Open |
| Tax Agent Bench (Vals AI) | 26.3% | 32.6% | Hy4 preview |
| Legal Research Bench (Vals AI) | 38.5% | 45.2% | Hy4 preview |
| Harvey's Legal Agent Benchmark (Vals AI) | Not measured | 8.8% | Only Hy4 preview measured |
| Excel Modeling Benchmark (Vals AI) | 53.7% | 58.1% | Hy4 preview |
| BioMysteryBench (Vals AI) | Not measured | 69.3% | Only Hy4 preview measured |
| Terminal-Bench-Science (Vals AI) | Not measured | 1.4% | Only Hy4 preview measured |
| APEX-Agents | 33.4% | Not measured | Only Muse Spark Open measured |
| Neither model has a result on the other 27 boards here | |||
ReasoningDirectional onlyPublic boards, shown as published, kept out of the index3 boards, none shared
| Benchmark | Muse Spark Open | Hy4 preview | 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% | Not measured | Only Muse Spark Open measured |
| Neither model has a result on the other 18 boards here | |||
MathDirectional onlyPublic boards, shown as published, kept out of the index1 board, none shared
| Benchmark | Muse Spark Open | Hy4 preview | Leader |
|---|---|---|---|
| ProofBench | Not measured | 75.0% | Only Hy4 preview measured |
| Neither model has a result on the other 12 boards here | |||
KnowledgeDirectional onlyPublic boards, shown as published, kept out of the index2 boards, none shared
| Benchmark | Muse Spark Open | Hy4 preview | Leader |
|---|---|---|---|
| LegalBench (Vals AI) | Not measured | 83.8% | Only Hy4 preview measured |
| MedCode (Vals AI) | Not measured | 43.3% | Only Hy4 preview measured |
| Neither model has a result on the other 15 boards here | |||
Web designDirectional onlyPublic boards, shown as published, kept out of the index3 boards, none shared
| Benchmark | Muse Spark Open | Hy4 preview | Leader |
|---|---|---|---|
| Design Arena: websites | 1311 | Not measured | Only Muse Spark Open measured |
| Design Arena: game dev | 1290 | Not measured | Only Muse Spark Open measured |
| LiveBench design | 60.3% | Not measured | Only Muse Spark Open measured |
| Neither model has a result on the other 6 boards here | |||
GeneralDirectional onlyPublic boards, shown as published, kept out of the index5 boards, none shared
| Benchmark | Muse Spark Open | Hy4 preview | Leader |
|---|---|---|---|
| Vals Index | Not measured | 53.2% | Only Hy4 preview measured |
| LiveBench data analysis | 60.2% | Not measured | Only Muse Spark Open measured |
| Public Benefits Bench (Vals AI) | Not measured | 68.6% | Only Hy4 preview measured |
| MedScribe (Vals AI) | Not measured | 83.6% | Only Hy4 preview measured |
| Long context reasoning (AA-LCR) | 78.3% | Not measured | Only Muse Spark Open measured |
| Neither model has a result on the other 41 boards here | |||
Image generationNot comparablePublic boards, shown as published, kept out of the index0 boards, none shared
| Benchmark | Muse Spark Open | Hy4 preview | 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
Hy4 preview costs less
Repository review
50K input + 3K output tokens
Hy4 preview costs less
Agent loop
200K input + 10K output tokens
Hy4 preview 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 | Tencent Hy4 preview |
|---|---|---|
| Maker | Meta | Tencent |
| Weights | Open weights | Open weights |
| Released | October 15, 2026 | August 28, 2026 |
| Context window | 1.05M | 1.05M |
| Input $/Mtok | $1.25 | $0.834 |
| Output $/Mtok | $4.25 | $2.501 |
| Coding index | 62.1 | 61.6 |
| Independent measurements behind it | 2 | 1 |
| Cost per solved task | Not computable | Not computable |
| Source | OpenRouter listing | OpenRouter listing |
Questions
Is Muse Spark Open better than Hy4 preview for coding?
Muse Spark Open and Hy4 preview are level for coding, 62.1 against 61.6 on the Vibe Coding Index, so price and context decide. Pick Hy4 preview when output tokens cost 1.7x less, or when what matters is LMArena WebDev or Terminal-Bench 4 (Vals AI), where it leads. Pick Muse Spark Open when the benchmark that matters is Finance Agent (Vals AI), where it leads.
Which is cheaper, Muse Spark Open or Hy4 preview?
Muse Spark Open costs $1.25 per million input tokens and $4.25 per million output tokens; Hy4 preview costs $0.834 and $2.501. Cost per solved task is known for neither of them.
Which has the bigger context window, Muse Spark Open or Hy4 preview?
Neither: both take 1.05M tokens.
How many benchmarks is the Muse Spark Open vs Hy4 preview comparison based on?
10 benchmarks have a result for both models as of October 21, 2026. Muse Spark Open's coding index rests on 2 independent benchmarks and Hy4 preview's on 1. Where only one model has a result, the page says so instead of naming a winner.