Step-5-Preview vs Muse Spark 1.3
API pricing, benchmark indices and specs — updated 19 October 2026.
meta · B · API-only
Input / 1M
$1.25
Output / 1M
$4.25
AA index
48.1
proprietary · 1M context
Specification comparison
Differences are highlighted; identical values are muted.
| Specification | Step-5-Preview | Muse Spark 1.3 |
|---|---|---|
| Deployment | Open weights · also via API | API-only (closed weights) |
| Parameters | 604.3 B | n/a — API-only |
| Architecture | Step5ForConditionalGeneration | n/a — API-only |
| Context length | 1,000,000 | 1,048,576 |
| Licence | other | Proprietary |
| Commercial use | Unknown | Per API terms |
| Languages | — | n/a — API-only |
| Downloads 30d | 2,467 | n/a — API-only |
| Downloads all time | 2 K | n/a — API-only |
| Quantizations on the Hub | SAFETENSORS | n/a — API-only |
| Gated | No | n/a — API-only |
| First seen on the Hub | 2026-09-20 | n/a — API-only |
| API input price / 1M tokens | $1.00 | $1.25 |
| API output price / 1M tokens | $2.70 | $4.25 |
| Est. cost per 1M input + 1M output tokens | $3.70 | $5.50 |
| Cached input / 1M tokens | $0.10 | $0.15 |
| AA Intelligence Index | 43.7 | 48.1 |
| AA Coding Index | — | 75.8 |
| AA Agentic Index | — | 55.5 |
| Max output tokens | 64,000 | 943,718 |
| API providers | 4 | 1 |
| Tool calling | Yes | Yes |
| Reasoning mode | Yes | Yes |
API cost
Estimated cost of 1M input + 1M output tokens via OpenRouter
Step-5-Preview
$3.70
Muse Spark 1.3
$5.50
Step-5-Preview is 1.5× cheaper at list price.
VRAM side by side
On RTX 4090 · 24 GB · 8K context unless noted
Step-5-Preview · fp16
806.5 GB / 24 GB