Devstral is an Apache-2.0, open-source coding model from Mistral AI and All Hands AI that’s trained to fix real GitHub issues through agent frameworks like OpenHands and SWE-Agent. It tops the open market with 46.8% on SWE-Bench Verified—beating models hundreds of billions of parameters larger—yet still runs on a single RTX 4090 or 32 GB Mac.
For developers, that means a free, self-hostable engine that can read an entire repo, locate a bug, and propose a passing patch without shipping code to a third party. Use it locally for privacy-sensitive work, drop it into agentic IDE plugins, or call the devstral-small-2505 API for cheap, high-accuracy automated bug fixing.