Baidu announces ERNIE 5.5 Flash Preview, a 280B parameter Mixture-of-Experts model optimized for high-speed inference and long-horizon coding tasks.

On November 11, 2026, Baidu officially announced the release of ERNIE 5.5 Flash Preview via its ERNIE portal. This release marks a significant milestone in the ERNIE evolution, serving as the first post-trained model built upon the ERNIE 5.5 Flash Base checkpoint that was released to the community on October 21.
For developers and AI engineers, this model represents a strategic shift toward high-efficiency, high-throughput intelligence. While the previous ERNIE 5.1 Preview successfully topped the LMArena Text Leaderboard as the premier Chinese model, the 5.5 Flash Preview focuses on the practical demands of production environments: speed, massive context, and complex agentic execution.
The ERNIE 5.5 Flash Preview is built on a sophisticated Mixture-of-Experts (MoE) architecture. This design allows the model to maintain a massive knowledge base while remaining computationally efficient during inference. By utilizing a sparse activation strategy, the model achieves a balance between deep reasoning capabilities and rapid response times.
A standout technical specification is the model's ability to handle massive datasets in a single pass. With a 1-million-token context window, developers can feed entire codebases, lengthy technical manuals, or massive legal documents into the model without losing coherence or context. This makes it an ideal candidate for advanced RAG (Retrieval-Augmented Generation) systems and complex data analysis.
The ERNIE 5.5 Flash Preview demonstrates exceptional performance in specialized domains, particularly in coding and automated reasoning. Unlike standard chat models, this preview is fine-tuned for 'long-horizon' tasks—meaning it can plan, execute, and self-correct over multiple steps. This was evidenced by launch demos where the model operated within an agent harness to perform end-to-end tasks in game development and 3D modeling.
In rigorous benchmarking, the model has shown highly competitive results. It excels in automation and technical reasoning, outperforming many contemporary models on specialized evaluation sets. The performance gains are not just theoretical; the model's efficiency is further bolstered by optimizations like ERNIE Evolve, which has been shown to significantly increase throughput on Kunlunxin hardware.
Baidu has made the ERNIE 5.5 Flash Preview available immediately via the Qianfan platform. As a 'Flash' tier model, it is positioned to be cost-effective for high-volume applications, providing a much lower price-to-performance ratio compared to larger, dense models.
Developers can integrate the model into their existing pipelines using standard RESTful APIs. While specific tier-based discounts may apply for enterprise users on the Qianfan platform, the base pricing is designed to compete directly with other high-speed frontier models.
The architecture of ERNIE 5.5 Flash Preview makes it uniquely suited for several high-value engineering use cases. Its strength in 'long-horizon' coding means it is not just a snippet generator, but a project assistant capable of fixing bugs across multiple files or building out entire modules from a high-level design specification.
Beyond coding, the model is a powerhouse for content creation and knowledge work. The integration of 3D modeling and video creation capabilities in its agentic demos suggests that Baidu is targeting the next generation of multimodal creative workflows, where the LLM acts as the central orchestrator for various specialized tools.
For developers looking to experiment with the model immediately, the API is live on the Qianfan platform. You can begin by setting up your credentials and testing the endpoint with the 1M token context window to evaluate its performance on your specific datasets.
Crucially for the open-source community, Baidu has announced a strategic pivot regarding the model's weights. While the Preview is currently closed-source, the weights for the ERNIE 5.5 Flash family are scheduled to be open-sourced under the Apache 2.0 license by November 25, 2026. This provides a massive opportunity for researchers to conduct post-training and fine-tuning for specialized local deployments.
API Pricing — Context: 1M tokens