AI tools · November 12, 2026

Baidu's ERNIE 5.5 Flash Preview is a 280B-parameter model with open weights due November 25

Baidu released ERNIE 5.5 Flash Preview on November 11, a 280-billion-parameter model that runs just 14 billion parameters per token — and says the full weights will be public under the Apache 2.0 license by November 25. The API is live now on Baidu's Qianfan platform and on OpenRouter, where it costs $0.28 per million input tokens and $1.13 per million output tokens, with a free variant listed.

The Preview is the chat-ready version of a base model Baidu open-sourced on November 5, trained from scratch on 33.5 trillion tokens with a one-million-token context window. Baidu pitches it for coding, 3D modeling, knowledge work, and content creation, and says it wrote an entire Unreal Engine game in C++ in a single 11-hour run. Baidu is blunt that this is a work in progress: its own release page calls the Preview "an intermediate checkpoint from post-training" and warns some capabilities may still fall short.

The numbers to treat carefully are the benchmarks — Baidu publishes them as chart images, not tables, and no independent evaluation exists yet. What is checkable is the calendar: November 25 is the date Baidu has committed to for the open weights. If they land under Apache 2.0 as promised, ERNIE 5.5 Flash becomes one of the largest permissively licensed models with a million-token window that anyone can download and run.

Why it matters

Open-weights models are the only way small teams and solo builders can run frontier-class AI without renting it by the token — and a 280B model with a million-token window under Apache 2.0 would be one of the biggest free downloads in AI. The catch is the date: until the weights actually appear, this is a promise, not a product. Mark November 25, and check the license file when it lands — the base model shipped under a custom license, not Apache 2.0.

Key facts

Released November 11, 2026; first post-trained version of the ERNIE 5.5 Flash base model from November 5
280B total parameters, 14B active per token; one-million-token context window
API live on Baidu Qianfan and OpenRouter at $0.28/$1.13 per million input/output tokens, with a free variant
Baidu says open weights arrive under Apache 2.0 by November 25, 2026
Baidu calls it an intermediate checkpoint: training is not finished and some capabilities may fall short
Benchmarks are Baidu's own chart images; no independent evaluation published yet

Sources

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