# SmolLM3 (3B)

> Compact dense model that experiments with leaving out positional encodings in selected layers.

| Property | Value |
| --- | --- |
| Lab | Hugging Face (United States) |
| Released | 2025-06-19 |
| Decoder type | Dense |
| Family | Dense |
| Scale | 3B parameters |
| Context window | 131,072 tokens |
| Attention | GQA with periodic NoPE layers |
| Layer mix | 36 GQA |
| KV cache / token (bf16) | 72 KiB (Low) |
| License | Apache License 2.0 |

**Key detail:** Every fourth layer omits RoPE to test a NoPE-style cadence.

## Architecture concepts

- [No Positional Embeddings (NoPE)](https://llm-atlas-7or.pages.dev/concepts/nope.md): Some or all layers drop explicit positional encodings and rely on the causal mask.
- [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.

## Links

- Architecture diagram: https://sebastianraschka.com/llm-architecture-gallery/images/architectures/smollm3-3b.webp
- View in article: https://magazine.sebastianraschka.com/p/the-big-llm-architecture-comparison#%C2%A77-smollm3
- config.json: https://huggingface.co/HuggingFaceTB/SmolLM3-3B-Base/blob/main/config.json
- Tech report: https://huggingface.co/blog/smollm3
- Source card (source of truth): https://sebastianraschka.com/llm-architecture-gallery/#card-smollm3-3b
- Web page: https://llm-atlas-7or.pages.dev/models/smollm3-3b/
- JSON: https://llm-atlas-7or.pages.dev/api/models/smollm3-3b.json

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