Best LLM APIs for writing (August 2026)
The models rated highest for writing and creative tasks, restricted to what FastMetal serves today.
Ranked by ELO on the public arena's Creative Writing board, restricted to models FastMetal serves. The order updates with the leaderboard.
| Links | |||||||
|---|---|---|---|---|---|---|---|
| 1 | Claude Fable 5 |  Anthropic | #1 · 1,507 | ¥1,787 | ¥8,935 | 1,000,000 | DetailsCompare |
| 2 | Claude Opus 5 | Anthropic | #3 · 1,489 | ¥893.5 | ¥4,467.5 | 1,000,000 | DetailsCompare |
| 3 | Claude Opus 4.7 | Anthropic | #6 · 1,480 | ¥840 | ¥4,200 | 1,000,000 | Details |
| 4 | Claude Opus 4.6 | Anthropic | #8 · 1,477 | ¥850 | ¥4,200 | 1,000,000 | Details |
| 5 | GPT-5.6 Sol |  OpenAI | #9 · 1,476 | ¥893.5 | ¥5,361 | 1,050,000 | DetailsCompare |
| 6 | Kimi K3 |  Moonshot | #12 · 1,471 | ¥536.1 | ¥2,680.5 | 1,048,576 | DetailsCompare |
| 7 | Gemini 3.5 Flash |  Google | #15 · 1,464 | ¥268.05 | ¥1,608.3 | 1,048,576 | DetailsCompare |
| 8 | Claude Opus 4.8 | Anthropic | #18 · 1,461 | ¥893.5 | ¥4,467.5 | 1,000,000 | DetailsCompare |
| 9 | Claude Sonnet 4.6 | Anthropic | #24 · 1,452 | ¥554.4 | ¥2,772 | 1,000,000 | Details |
| 10 | GLM 5.1 |  Z.ai | #25 · 1,450 | ¥250.18 | ¥786.28 | 204,800 | Details |
Click a column heading to re-sort; the table opens in this category's ranking order. Prices are yen per 1M tokens before tax; context is in tokens.
Frequently asked questions
- What is this ranking based on?
- Ranked by ELO on the public arena's Creative Writing board, restricted to models FastMetal serves. The order updates with the leaderboard.
- How is pricing decided?
- Each model has a yen price per 1M tokens (before tax), drawn from a prepaid balance as you use it. There is no subscription or monthly fee.
- Can I use the top models with one API key?
- Yes. Every model on this page is served from FastMetal's OpenAI-compatible endpoint under one API key; switching is a change to the model string.
Every model above runs on one API key
Create an account and add credit to call these models from the browser chat and the API. No monthly fee.