# Laguna XS 2.1 (33B)

> Poolside's 33B Laguna refresh extends the sparse MoE architecture to 262k context while keeping about 3B parameters active per token.

| Property | Value |
| --- | --- |
| Lab | Poolside (United States) |
| Released | 2026-07-02 |
| Decoder type | Sparse MoE |
| Family | Sparse MoE |
| Scale | 33B total, 3B active (9.1% active) |
| Context window | 262,144 tokens |
| Attention | Gated GQA with QK-Norm and 3:1 sliding-window/global attention |
| Layer mix | 30 sliding-window + 10 global GQA |
| KV cache / token (bf16) | 160 KiB (Moderate) |
| License | OpenMDW License 1.1 |

**Key detail:** Uses 256 routed experts with top-8 routing plus one shared expert, a dense first layer, and per-layer query-head counts.

## Architecture concepts

- [Grouped-Query Attention (GQA)](https://llm-atlas-7or.pages.dev/concepts/gqa.md): Several query heads share one key/value head, shrinking the KV cache with little quality loss.
- [QK-Norm (QK-Norm)](https://llm-atlas-7or.pages.dev/concepts/qk-norm.md): RMSNorm applied to queries and keys before attention to keep logits well-behaved.
- [Sliding Window Attention (SWA)](https://llm-atlas-7or.pages.dev/concepts/swa.md): Some layers only attend to a local window of recent tokens instead of the whole context.
- [Mixture of Experts (MoE)](https://llm-atlas-7or.pages.dev/concepts/moe.md): Many feed-forward experts, but a router sends each token to only a few of them.
- [Layer-wise attention budgeting (Attention budgeting)](https://llm-atlas-7or.pages.dev/concepts/attention-budgeting.md): Different layers get different attention budgets: head counts, windows or full context.

## Links

- Architecture diagram: https://sebastianraschka.com/llm-architecture-gallery/images/architectures/laguna-xs-2-1.webp
- config.json: https://huggingface.co/poolside/Laguna-XS-2.1/blob/main/config.json
- License: https://huggingface.co/poolside/Laguna-XS-2.1/blob/main/LICENSE.md
- Tech report: https://huggingface.co/poolside/Laguna-XS-2.1
- Source card (source of truth): https://sebastianraschka.com/llm-architecture-gallery/#card-laguna-xs-2-1
- Web page: https://llm-atlas-7or.pages.dev/models/laguna-xs-2-1/
- JSON: https://llm-atlas-7or.pages.dev/api/models/laguna-xs-2-1.json

_Data from Sebastian Raschka's LLM Architecture Gallery (https://sebastianraschka.com/llm-architecture-gallery/). Synced 2026-11-04._