Tiny MoE ColBERT retrievers: 1.5M encoder to 115M model rivaling larger dense models

tomaarsen · x · 2026-10-26

VAGOsolutions released the SauerkrautLM-MoEdernColBERT collection on Hugging Face: multilingual ColBERT retrievers built on the MoEdernBERT architecture, available in 1.5M, 27M and 115M sizes with GGUF and CoreML builds.

Sentence transformers maintainer tomaarsen notes this scale of MoE retrieval is fascinating: the 1.5M encoder is tiny, while the 115M model competes with much larger dense models. He attributes part of the quality to multi-vector retrieval — each token keeps a 128-d vector and MaxSim lets query tokens match different document tokens, so far more vectors must be stored and scored than one dense vector per text.

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