Qwen3-Coder vs Claude Sonnet 5: open coding model vs closed agent
FastMetal no longer offers Qwen3-Coder. This comparison is kept as a record of how the two models stacked up when we served both; Claude Sonnet 5 is still available, and what we serve today is on the models page.
If you are choosing a model for coding alone, Alibaba's open Qwen3-Coder and Anthropic's Claude Sonnet 5 are two very different answers. Qwen3-Coder is cheap and suited to batch work; Sonnet 5 is careful and suited to working alongside you.
The short version: Qwen3-Coder for running overnight batches and large automation cheaply, Sonnet 5 for interactive work you need done right.
Specs
| Qwen3-Coder | Claude Sonnet 5 | |
|---|---|---|
| Lab | Alibaba | Anthropic |
| License | Apache 2.0 (open weights) | Closed |
| Context window | 256K native, ~1M extended | 1M tokens |
| Best at | Tool calls, low cost, batch work | Finishing multi-step jobs, checking its own work |
Claude Sonnet 5 is anthropic-claude-sonnet-5 on FastMetal, at $2.11 per million input tokens and $10.55 per million output tokens on the USD list as of October 24, 2026.
Where each is stronger
Qwen3-Coder is an open mixture-of-experts model built for agentic coding. Reviewers reported a 100% tool-call success rate: when it decides to run a command, it runs it correctly. It reads 256K tokens of context natively and about a million with extension, enough to load a whole repository. Its biggest advantage is cost, with one estimate putting its cost per solved problem at a few percent of a closed top-tier model's.
Claude Sonnet 5 is billed by Anthropic as its most agentic Sonnet, built to carry a multi-step job to the end. Developers said it checked its own work without being asked and finished tasks earlier Sonnets abandoned.
What each gets wrong
Qwen3-Coder is slow. Reports put its average time per task at several times that of Claude's top models. That rules it out for live pair programming; it belongs on batch jobs such as overnight refactors, PR triage and migration scripts. It also trails the general-purpose frontier models in raw capability.
Sonnet 5 is slow on easy work, for a different reason. Reviewers found it slower than Sonnet 4.6 on simple tasks, because it runs tests even for small changes and re-plans mid-task. Its place between Haiku and Opus is also harder to justify than it should be.
Which fits which job
- Qwen3-Coder: overnight batch refactors, PR triage, bulk documentation and migrations, automation where cost comes first.
- Claude Sonnet 5: multi-step tasks you work through interactively and need done correctly, where self-checking and cautious behavior matter.
FAQ
Which is cheaper? Qwen3-Coder, by a wide margin per solved problem. It is no longer on FastMetal; current prices for what we serve are on the models page.
Which is better for real-time use? Claude Sonnet 5. Qwen3-Coder's latency suits batch work, not interactive sessions.
Which is better outside English? We couldn't find a published benchmark that isolates non-English quality for either model. If your work is mostly in another language, test with your own prompts.
Bottom line
Qwen3-Coder for cheap batch work, Claude Sonnet 5 for careful interactive coding. Even among coding-focused models, latency and cost split the roles cleanly.
For Sonnet 5 against today's alternatives, see Claude Sonnet 5 vs GPT-5.6 Sol and GPT-5.6 Terra vs Claude Sonnet 5.