Editorial illustration for Alibaba open-sources Qwen3.5-Medium models with Sonnet 4.5 performance locally
Qwen 3.5: Tiny AI Models Beat Massive Predecessors
Alibaba open-sources Qwen3.5-Medium models with Sonnet 4.5 performance locally
Alibaba just dropped a bomb on the open-source AI world. The Qwen3.5-Medium models are here, and they match Sonnet 4.5’s performance, on your local machine. That’s not a headline; it’s a seismic shift.
The company has released the 35B-A3B-Base model along with instruct-tuned versions, giving researchers a playground that rivals the best proprietary systems. But the real magic is in the thinking. Qwen 3.5 defaults to a native reasoning mode.
Before it answers, it works through complex logic internally, wrapping that chain of thought in `
Base Model Release: In a move to support the research community, Alibaba has open-sourced the Qwen3.5-35B-A3B-Base model alongside the instruct-tuned versions. Product: Intelligence that 'thinks' first Qwen 3.5 introduces a native "Thinking Mode" as its default state. Before providing a final answer, the model generates an internal reasoning chain--delimited by
tags--to work through complex logic.The product lineup is tailored for varying hardware environments: Qwen3.5-27B: Optimized for high efficiency, supporting a context length of over 800K tokens. Qwen3.5-Flash: The production-grade hosted version, featuring a default 1 million token context length and built-in official tools.
This isn’t just another open-source release. It’s a direct challenge to the assumption that frontier reasoning must live in the cloud behind an API key. Alibaba has handed researchers and developers a model that matches Sonnet 4.5’s output, on a local machine.
The default thinking mode isn’t a gimmick; it’s a fundamental shift in how we interact with open-source intelligence. No more black-box answers. You get the chain of thought, the internal deliberation, and then the result.
And because the lineup scales from 27B to the Flash hosted version, the barrier to entry collapses. The research community doesn’t have to beg for access. It can run, modify, and build on top of this reasoning engine today.
That changes the power dynamic. Proprietary leaders no longer hold the monopoly on structured, step-by-step logic. The playing field just got leveled, and Alibaba put the lever in your hands.
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Common Questions Answered
What makes the Qwen3.5-35B-A3B model unique in Alibaba's new lineup?
The Qwen3.5-35B-A3B is a sparse Mixture-of-Experts (MoE) model with only 3 billion active parameters out of 35 billion total. Remarkably, it outperforms the previous flagship Qwen3-235B-A22B model while being seven times smaller, demonstrating significant efficiency and performance improvements.
How does the new Qwen 3.5 'Thinking Mode' work?
Thinking Mode is the default reasoning approach where the model pauses to generate an internal reasoning chain before providing a final answer. This approach mimics a more deliberate thought process, allowing the model to work through complex logic before delivering its response.
What licensing options are available for the Qwen 3.5 Medium series models?
The Qwen 3.5 Medium series models are released under the Apache 2.0 license, which allows for both personal and commercial use. The models are currently hosted on platforms like Hugging Face and ModelScope, making them easily accessible to researchers and developers.
Further Reading
- Qwen 3.5 - Advanced AI Model Created by Alibaba Cloud — Overchat.ai
- Qwen3-Coder-Next: The Complete 2026 Guide to Running Powerful AI Coding Agents Locally — Dev.to
- Qwen3.5 397B A17B (Reasoning) vs Claude 4.5 Sonnet (Reasoning) — Artificial Analysis
- Qwen3.5 Reviews in 2026 — SourceForge
