SWE-1! The First AI for Software Engineering by Windsurf That You Shouldn’t Miss

Kattiya Jantas
May 16
2 min read

On May 15, 2025, Windsurf launched a new family of AI models under the name SWE-1, the first model specifically designed to support all stages of Software Engineering—not just code generation like traditional models.

Meet the SWE-1 Model Family

SWE-1

Comparable in capability to Claude 3.5 Sonnet
High proficiency in tool-call reasoning
Free to use for paid users during the promotional period (0 credits)

SWE-1-lite

A mid-sized model with better performance than the previous Cascade Base
Available to both free and paid users without usage limits

SWE-1-mini

Lightweight and high-speed model
Used in the Windsurf Tab for predictive and passive user assistance
Supports all user types

Why Did Windsurf Create SWE-1?

Code generation is just one part of the software engineering workflow. In the real world, engineers must also test code, use terminals, collaborate with others, analyze user feedback, and more.

Windsurf recognized this complexity and developed a model capable of handling real-world software engineering tasks, aiming to accelerate the development process by up to 99%.

Key Features of SWE-1

Supports incomplete work: Understands the context across multiple surfaces like terminal, browser, code, and documentation
Learns from real usage in Cascade: Understands user intentions and collaborates fluidly
Flow Awareness system: Tracks user actions continuously—whether typing code, opening a terminal, or previewing in a browser

SWE-1 Performance

1. Offline Evaluation

Performs on par with frontier models
Outperforms many open-weight models like Deepseek and Qwen
Handles ongoing tasks well (Conversational SWE Task Benchmark)
Solves tasks from start to passing unit tests (End-to-End SWE Task Benchmark)

2. Real-World Testing

Delivers more working code than competitors (Daily Lines Contributed)
High engagement with files edited by users (Cascade Contribution Rate)

“Flow Awareness”: The Secret Behind SWE-1

What sets SWE-1 apart is its Flow Awareness system, integrated into Windsurf Editor and Cascade. It enables the AI to understand user context in real time, such as:

Recognizing code edits in the editor
Understanding terminal errors
Knowing what previews the user is viewing in the browser
Tracking clipboard and search queries within the IDE

This shared timeline concept allows the AI and user to seamlessly take turns working—forming the foundation of AI flows, which Windsurf aims to make the best in the world.

The Future of SWE Models

SWE-1 is just the beginning. Windsurf plans to continuously invest and improve its SWE models to surpass top-tier models from major research labs in terms of both quality and cost-efficiency.

The First True AI for Full-Stack Software Engineering

SWE-1 marks the first major step in developing AI to support end-to-end software engineering, going beyond code to intelligently respond to everything developers do.

If you're a developer—or have a dev team looking for tools to work faster and more accurately—Windsurf SWE-1 is the AI you should definitely try!

Sources: TechCrunch, Windsurf