{
  "slug": "gpt-oss-20b",
  "order": 19,
  "name": "GPT-OSS (20B)",
  "baseTitle": "GPT-OSS 20B",
  "company": "OpenAI",
  "country": "United States",
  "flag": "🇺🇸",
  "date": "2025-08-04",
  "decoderType": "Sparse MoE",
  "attention": "GQA with alternating sliding-window and global layers",
  "layerMix": "12 sliding-window + 12 global",
  "scale": "21B total, 3.6B active (17.1% active)",
  "totalParams": 21000000000,
  "activeParams": 3600000000,
  "context": "128,000",
  "contextTokens": 128000,
  "license": "Apache License 2.0",
  "kvCacheText": "48 KiB",
  "kvCacheKiB": 48,
  "kvCacheLevel": "Low",
  "summary": "OpenAI's smaller open-weight MoE model favors width and alternating local/global attention.",
  "keyDetail": "Wider and shallower than Qwen3, with attention bias and sink mechanisms.",
  "image": {
    "full": "https://sebastianraschka.com/llm-architecture-gallery/images/architectures/gpt-oss-20b.webp",
    "thumb": "https://sebastianraschka.com/llm-architecture-gallery/images/architectures/thumbnails/gpt-oss-20b.webp",
    "alt": "Figure 26: GPT-OSS 20B",
    "width": 960,
    "height": 906
  },
  "articleUrl": "https://magazine.sebastianraschka.com/p/the-big-llm-architecture-comparison#%C2%A79-gpt-oss",
  "links": [
    {
      "label": "View in article",
      "href": "https://magazine.sebastianraschka.com/p/the-big-llm-architecture-comparison#%C2%A79-gpt-oss",
      "title": null
    },
    {
      "label": "config.json",
      "href": "https://huggingface.co/openai/gpt-oss-20b/blob/main/config.json",
      "title": "openai/gpt-oss-20b"
    },
    {
      "label": "License",
      "href": "https://huggingface.co/openai/gpt-oss-20b/blob/main/LICENSE",
      "title": null
    },
    {
      "label": "Tech report",
      "href": "https://cdn.openai.com/pdf/419b6906-9da6-406c-a19d-1bb078ac7637/oai_gpt-oss_model_card.pdf",
      "title": null
    }
  ],
  "concepts": [
    {
      "slug": "gqa",
      "label": "GQA",
      "name": "Grouped-Query Attention",
      "url": "https://llm-atlas-7or.pages.dev/concepts/gqa/"
    },
    {
      "slug": "swa",
      "label": "SWA",
      "name": "Sliding Window Attention",
      "url": "https://llm-atlas-7or.pages.dev/concepts/swa/"
    },
    {
      "slug": "moe",
      "label": "MoE",
      "name": "Mixture of Experts",
      "url": "https://llm-atlas-7or.pages.dev/concepts/moe/"
    }
  ],
  "aai": {
    "v4": {
      "label": "AA Intelligence Index v4.3.2",
      "total": 9,
      "profile": {
        "General": 12.8,
        "Scientific": 6.2,
        "Coding": 19.4,
        "Agents": 0
      },
      "url": "https://artificialanalysis.ai/models/gpt-oss-20b"
    }
  },
  "sourceUrl": "https://sebastianraschka.com/llm-architecture-gallery/#card-gpt-oss-20b",
  "family": "moe",
  "url": "https://llm-atlas-7or.pages.dev/models/gpt-oss-20b/",
  "markdownUrl": "https://llm-atlas-7or.pages.dev/models/gpt-oss-20b.md"
}