Baidu releases 280-billion-parameter ERNIE-5.5-Flash-Base

Baidu has released ERNIE-5.5-Flash-Base as an open foundation model with 280 billion parameters. The mixture-of-experts system activates 14 billion parameters for each input. It was pretrained on 33.5 trillion tokens with a training context of up to 128,000 tokens.

The model is distributed without fine-tuning or post-training. Baidu said developers are expected to adapt it for their own uses, while a post-trained version is planned for release later. During fine-tuning and inference, the system is designed to support contexts of up to one million tokens.

Baidu’s benchmarks compared ERNIE 5.5 Flash Base with DeepSeek-V4-Flash-Base, Hy3-preview-Base and MiMo-V2.5-Base using the same evaluation pipeline. The tests covered exams, STEM, reasoning, knowledge, code, multilingual performance and long-context tasks. According to Baidu, ERNIE 5.5 Flash Base is competitive with similarly sized open foundation models on reasoning, coding and long-context tasks. Its weights are available on Hugging Face in FP8 and BF16 formats.