Compare models
Pick up to 4. Every model here is free in free-pi.
| Attribute | Solar Pro 4 | Particle | GPT-6.1 Terra | GPT-6.1 Sol Flex |
|---|---|---|---|---|
| Maker | Upstage | — | OpenAI | OpenAI |
| Usage in free-pi | ~0.6x usage | 🔥 Free Unlimited: limited time | premium, uses allowance fast · ~20x usage | slower · ~41x usage |
| Intelligence index | 28.2 | — | 51.3 | 54.6 (best) |
| Coding index | 52.7 | — | — | — |
| Context window | 524,288 tokens | — | 1,050,000 tokens (best) | 1,050,000 tokens (best) |
| Max output | 131,072 tokens (best) | — | 128,000 tokens | 128,000 tokens |
| Inputs | Text | — | Text, image, file (best) | Text, image, file (best) |
| Tool calling | Yes | — | Yes | Yes |
| Reasoning effort | Yes | — | Yes | Yes |
| Structured output | Yes | — | Yes | Yes |
| Released | Aug 10, 2026 | — | Oct 26, 2026 | Sep 29, 2026 |
| Model page | Model page | Model page | Model page | Model page |
Stats refreshed automatically. Usage rate from free-pi. Green marks the best value in each row. “—” means no figure is available.