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Aleph Alpha Open-Sources Kolibri-1

Germany's Aleph Alpha open-sourced Kolibri-1, a 78B-parameter bilingual reasoning MoE with only 3.46B active parameters, on October 3. The release quickly drew community attention as a milestone for European open-source AI.

2026-10-03 ~ 2026-10-06 · 2 episodes · 17 posts

Episode 1 · Aleph Alpha open-sources Kolibri-1: a 78B MoE with only 3.46B active params (2026-10-03, 14 posts)

German AI company Aleph Alpha open-sourced its reasoning MoE model Kolibri-1 on Hugging Face on October 3 (German Unity Day), where it quickly trended. Under the Apache 2.0 license, it is positioned as a sovereign, European open-weight model: trained from scratch entirely in Germany, not a Qwen fine-tune, with a focus on German and English bilingual capability after months of pre- and post-training.

Confirmed

  • Specs: 78.1B total parameters, only 3.46B active per token (4.4%), context length up to 1M tokens
  • Architecture details (per @TejasKumar): 384 small experts per layer, with the router activating 6 per token — roughly 3.5B parameters running per word
  • Benchmark performance (per @TejasKumar): 96.9% on AIME 2025, beating all tested MoE models of similar or larger size, including those with more active parameters per token
  • Release format: available in vLLM and safetensors formats with an accompanying arXiv paper; weights can run on users' own hardware. Per @QuixiAI, the weights are in FP8 and run directly, and a feature request has already been filed for support in the open-source inference engine colibri (39.5k stars)
  • The model repo includes chat template configuration supporting system prompts, reasoning effort settings, and tool-calling format (per @JiliJeanlouis)
  • Third party Tesseracted Labs is hosting the model, letting users try it free in the browser for a few days without GPU or registration, with Brave Search web search enabled (per @FrankNoeBerlin)

Unconfirmed

  • Benchmarks such as the 96.9% AIME score currently come mainly from the publisher's materials and relayers like @TejasKumar, and await independent third-party verification

Why it matters

  • This is a flagship open-source result for Europe's "sovereign AI" route: trained and released entirely in Germany, offering Europe a controllable option independent of the US and China
  • The very low activation ratio (4.4%) implies much lower inference cost; if the benchmarks hold up under third-party testing, it will be a strong contender in the efficient-reasoning track
  • Free third-party trial access lowers the barrier to entry and helps the community build independent evaluations quickly

Episode 2 · Aleph Alpha Open-Sources Kolibri: 78B-Parameter Model with 1M Context (2026-10-05, 3 posts)

Germany's Aleph Alpha has open-sourced Kolibri, a 78.1B-parameter German-English MoE model under Apache 2.0 that activates only about 3.46B parameters per token and supports up to 1M-token context. Positioned for European sovereign use cases, it is seen as surpassing Mistral.