{
  "slug": "reflection-beam-501b",
  "order": 112,
  "name": "Reflection Beam (501B)",
  "baseTitle": "Reflection Beam 501B",
  "company": "Reflection",
  "country": "United States",
  "flag": "🇺🇸",
  "date": "2026-10-16",
  "decoderType": "Sparse MoE",
  "attention": "Gated GQA with QK-Norm and sliding-window/global attention",
  "layerMix": "43 sliding-window + 9 global GQA",
  "scale": "501.3B total, 23.4B active (4.7% active)",
  "totalParams": 501300000000,
  "activeParams": 23400000000,
  "context": "1,048,576",
  "contextTokens": 1048576,
  "license": "Apache License 2.0",
  "kvCacheText": "208 KiB",
  "kvCacheKiB": 208,
  "kvCacheLevel": "High",
  "summary": "Text-only MoE decoder with three dense FFN layers followed by 49 expert layers. Each MoE layer activates 8 of 256 experts without a shared expert.",
  "keyDetail": "Combines 512-token local RoPE attention with global NoPE and query scaling. Uses sandwich RMSNorm, depth-scaled residuals, and a final logit softcap of 30.",
  "image": {
    "full": "https://sebastianraschka.com/llm-architecture-gallery/images/architectures/reflection-beam.webp",
    "thumb": "https://sebastianraschka.com/llm-architecture-gallery/images/architectures/thumbnails/reflection-beam.webp",
    "alt": "Figure 1: Reflection Beam 501B",
    "width": 960,
    "height": 944
  },
  "articleUrl": null,
  "links": [
    {
      "label": "config.json",
      "href": "https://huggingface.co/reflection/Beam-1.0-501B-A23B/blob/main/config.json",
      "title": "reflection/Beam-1.0-501B-A23B"
    },
    {
      "label": "License",
      "href": "https://huggingface.co/reflection/Beam-1.0-501B-A23B/blob/main/LICENSE",
      "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": "gated-attention",
      "label": "Gated Attention",
      "name": "Gated Attention",
      "url": "https://llm-atlas-7or.pages.dev/concepts/gated-attention/"
    },
    {
      "slug": "moe",
      "label": "MoE",
      "name": "Mixture of Experts",
      "url": "https://llm-atlas-7or.pages.dev/concepts/moe/"
    },
    {
      "slug": "qk-norm",
      "label": "QK-Norm",
      "name": "QK-Norm",
      "url": "https://llm-atlas-7or.pages.dev/concepts/qk-norm/"
    },
    {
      "slug": "nope",
      "label": "NoPE",
      "name": "No Positional Embeddings",
      "url": "https://llm-atlas-7or.pages.dev/concepts/nope/"
    }
  ],
  "aai": {
    "v5": {
      "label": "AA Intelligence Index v5.0",
      "total": 17.7,
      "profile": {
        "Knowledge Work": 26.3,
        "Coding": 4.5,
        "Science": 10.9,
        "General": 29.2
      },
      "url": "https://artificialanalysis.ai/models/reflection-beam"
    }
  },
  "sourceUrl": "https://sebastianraschka.com/llm-architecture-gallery/#card-reflection-beam-501b",
  "family": "moe",
  "url": "https://llm-atlas-7or.pages.dev/models/reflection-beam-501b/",
  "markdownUrl": "https://llm-atlas-7or.pages.dev/models/reflection-beam-501b.md"
}