Alibaba's new open source Qwen3.5-Medium models offer Sonnet 4.5 performance on local computers

Alibaba's now famed Qwen AI development team has done it again: a little more than a day ago, they released the Qwen3.5 Medium Model series consisting of four new large language models (LLMs) with support for agentic tool calling, three of which are available for commercial usage by enterprises and indie developers under the standard open source Apache 2.0 license.

But the big twist with the open source models is that they offer comparably high performance on third-party benchmark tests to similarly-sized proprietary models from major U.S. startups like OpenAI or Anthropic, actually beating OpenAI's GPT-5-mini and Anthropic's Claude Sonnet 4.5 — the latter model which was just released five months ago. 

And, the Qwen team says it has engineered these models to remain highly accurate even when "quantized," a process that reduces their footprint further by reducing the numbers by which the model's settings are stored from many values to far fewer.