gpt-oss-20b is an open-weight 21B parameter model released by OpenAI under the Apache 2.0 license. It uses a Mixture-of-Experts (MoE) architecture with 3.6B active parameters per forward pass, optimized for...
OpenAI: gpt-oss-20b — OpenAI. Context window 131,072 tokens. API pricing (per 1M tokens): Input $0.018, Output $0.09. License: Proprietary. LMArena 1,288. GPQA Diamond 60.8%.
| Provider | OpenAI |
|---|---|
| API model ID | openai/gpt-oss-20b |
| Tier | Mid |
| Context window | 131,072 tokens |
| Max output | 32,768 tokens |
| License | Proprietary |
| API pricing (per 1M tokens) · Input | $0.018 |
| API pricing (per 1M tokens) · Output | $0.09 |
| LMArena | 1,288 (gpt-oss-20b) |
| GPQA Diamond | 60.8% |
LMArena (CC-BY 4.0, best reasoning setting, 2026-10-02) · GPQA Diamond: Epoch AI (CC-BY 4.0)
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