Release2026-11-05

Baidu released ERNIE-5.5-Flash-Base as an open base model. It is a 280B-parameter sparse Mixture-of-Experts model. It activates 14B parameters per token. It was pre-trained from scratch on 33.5T tokens. Training used a context window of up to 128K tokens. Fine-tuning and inference support a 1M-token context. The release includes no mid- or post-training. The architecture uses hybrid sparse attention and latent MoE. It also introduces manifold-constrained hyper-connections and a MultiMax output head. The tokenizer uses right-to-left grouping for numbers. The model is available on HuggingFace.

What changed

No prior open base model from Baidu combined hybrid sparse attention, latent MoE, and 1M-token context support.

What it unlocks

Developers can fine-tune or further train a high-capability base model without starting pre-training from scratch.

  • 280B total parameters
  • 14B activated per token
  • 33.5T tokens pre-trained
  • 128K training context

What you need to act on it

  • access to HuggingFace or Baidu's model repository
  • compute resources for 280B-parameter model inference or fine-tuning

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