# ERNIE 5.5 Flash Preview — Baidu's 280B MoE for agentic coding

> Baidu's 280B mixture-of-experts model with 14B active parameters, built for long agentic coding and office work.

- Org: Baidu
- Date: 2026-11-11
- Category: model
- Source: https://ernie.baidu.com/release/ernie-5-5-flash-preview
- Canonical page: https://ai-tldr.dev/releases/baidu-ernie-5-5-flash-preview/

## In short

ERNIE 5.5 Flash Preview is Baidu's first post-trained model on ERNIE 5.5 Flash Base: 280B total and 14B active parameters, 1M-token context. It is on Qianfan and free on OpenRouter; Apache-2.0 weights are promised.

## What it is

ERNIE 5.5 Flash Preview is the first post-trained model built on ERNIE 5.5 Flash Base, the 280B base checkpoint Baidu released on November 5. Baidu calls the preview an intermediate checkpoint: post-training is still running, and the official release will include improvements.

## How it works

The model is a sparse mixture-of-experts: only 14B of its 280B parameters run for each token, which keeps decoding fast for a model this size. It has a 1M-token context window. Baidu shows it on long agent tasks, such as an 11-hour coding run that built a third-person game in Unreal Engine 5.8, Blender scenes and FreeCAD models.

## Why it matters

Baidu's own table puts the preview ahead of Claude Opus 5.5 and GPT-6.1 Sol on AutomationBench and SpreadsheetBench V2, but well behind both on Terminal-Bench 4.0, and many competitor scores are Baidu's own runs. With a free OpenRouter endpoint and Apache-2.0 weights promised, developers get another cheap Chinese option for agent work.

## Who it's for

developers building coding and office agents

## Try it

https://openrouter.ai/baidu/ernie-5.5-flash-preview:free

## Quick facts

- Maker: Baidu
- Architecture: MoE, 280B total / 14B active
- Context window: 1M tokens
- Availability: Baidu Qianfan API + OpenRouter (free)
- Weights: Apache-2.0, announced, no date
- Status: Preview, an intermediate post-training checkpoint

## FAQ

### Are ERNIE 5.5 Flash Preview weights open source?

Not yet. Baidu says the ERNIE 5.5 Flash Preview weights will be released under Apache 2.0 soon, without a date. The base checkpoint, ERNIE 5.5 Flash Base, is already on Hugging Face in FP8 and BF16 under Baidu's own ERNIE 5.5 Flash Base Model License.

### Where can I use ERNIE 5.5 Flash Preview?

Baidu offers ERNIE 5.5 Flash Preview through its Qianfan API platform and as a free model on OpenRouter under the id baidu/ernie-5.5-flash-preview:free. Baidu's announcement does not list API prices, so the free OpenRouter route is the simplest way to test the model.

### How does ERNIE 5.5 Flash Preview compare with Claude Opus 5.5 and GPT-6.1 Sol?

In Baidu's table, ERNIE 5.5 Flash Preview scores 61.9 on AutomationBench against 58.0 for Claude Opus 5.5 and 49.3 for GPT-6.1 Sol. On Terminal-Bench 4.0 it scores 46.5, behind GPT-6.1 Sol at 56.1 and Claude Opus 5.5 at 63.6. Baidu ran many competitor scores itself.

### What are the limits of the ERNIE 5.5 Flash Preview release?

Baidu describes ERNIE 5.5 Flash Preview as an intermediate checkpoint from post-training. Baidu says some capabilities may still fall short, that training continues, and that the official ERNIE 5.5 Flash release will improve on it. The model is text-only; Baidu used a Claude Opus 5.5 tool for image understanding in BlenderWorld.

## Links

- [Announcement](https://ernie.baidu.com/release/ernie-5-5-flash-preview)
- [OpenRouter (Free)](https://openrouter.ai/baidu/ernie-5.5-flash-preview:free)
- [ERNIE 5.5 Flash Base](https://ernie.baidu.com/release/ernie-5-5-flash-base/)
- [Base Weights (HF)](https://huggingface.co/baidu/ERNIE-5.5-Flash-Base)