Muse Spark 1.3 Contributor vs Solar Pro 4
Pricing, context window and real answers (September 2026)
Muse Spark 1.3 Contributor (Meta) and Solar Pro 4 (Upstage), compared as you can actually call them on FastMetal. Both are served from the same OpenAI-compatible endpoint and API key; switching is a change to the model string.
Specs and pricing
 Muse Spark 1.3 Contributor | Solar Pro 4 | |
|---|---|---|
| Provider | Meta | Upstage |
| Input (per 1M tokens) | ¥17.59 | ¥16.08 |
| Output (per 1M tokens) | ¥35.18 | ¥64.33 |
| Typical cost (1,000 in + 500 out tokens × 1,000 calls) | ¥35 | ¥48 |
| Context window | 1,048,576 tokens | 524,288 tokens |
| Release date | 9/2/2026 | 8/10/2026 |
| Input modalities | text, image, video, file, audio | text |
| Throughput (p50) | — | — |
| Arena · overall | Unranked | #177 · ELO 1,376 |
| Arena · Japanese | Unranked | Unranked |
| Arena · coding | Unranked | #144 · ELO 1,449 |
Prices are FastMetal's yen rates before tax. Arena ranks are as of the latest leaderboard scrape.
Which should you pick?
- On price, Muse Spark 1.3 Contributor: ¥35.18 per 1M output tokens, 45% less than Solar Pro 4.
- For long documents, Muse Spark 1.3 Contributor: a 1,048,576-token context window against 524,288 for Solar Pro 4.
- If in doubt, try both on the same key. Switching is a change to the model string, and each is billed at its own rate.
Frequently asked questions
- Which is cheaper, Muse Spark 1.3 Contributor or Solar Pro 4?
- Per 1M output tokens, Muse Spark 1.3 Contributor is ¥35.18 and Solar Pro 4 is ¥64.33 on FastMetal (yen, before tax), so Muse Spark 1.3 Contributor is cheaper.
- How do the context windows of Muse Spark 1.3 Contributor and Solar Pro 4 compare?
- Muse Spark 1.3 Contributor takes 1,048,576 tokens; Solar Pro 4 takes 524,288.
- Can I use Muse Spark 1.3 Contributor and Solar Pro 4 with the same API key?
- Yes. On FastMetal's OpenAI-compatible endpoint, switch by passing "muse-spark-1.3-contributor" or "solar-pro4" as the model. Each is billed at its own rate from the same prepaid balance.
Try both on one API key
Create an account and add credit to call Muse Spark 1.3 Contributor and Solar Pro 4 from the browser chat and the API. No monthly fee.
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