Windsurf, an AI-native IDE forked from VS Code, has carved out a niche in the vibe-coding scene by integrating advanced large language models (LLMs) like Claude Sonnet 4 from Anthropic. Launched in May 2025, Claude Sonnet 4 powers Windsurf’s Cascade agent, delivering context-aware coding assistance that rivals top competitors like Cursor and GitHub Copilot. This review dives into Windsurf’s performance with Claude Sonnet 4, its standout features, token usage mechanics, and whether it’s worth the hype for developers in 2025.
Why Windsurf with Claude Sonnet 4?
Windsurf positions itself as an “agentic IDE,” meaning it goes beyond basic code completion to act as a collaborative partner. Claude Sonnet 4, known for its 72.7% score on SWE-bench and enhanced reasoning, is a perfect fit for this vision. It excels in generating clean code, navigating large codebases, and handling multi-step tasks with minimal errors. Unlike its predecessor, Sonnet 3.7, it offers improved instruction-following and a 64K output token capacity, ideal for complex projects.
Windsurf’s Cascade agent leverages Sonnet 4 for features like inline suggestions, on-demand refactoring, and autonomous file edits. Recent updates, including Wave 11 in July 2025, added voice input and deeper browser integration, making it a dynamic tool for modern developers. But how does it perform in practice, and what’s the deal with token usage?
Performance and Features
Claude Sonnet 4 shines in Windsurf for its precision and context awareness. It can read entire project structures—import trees, variables, and comments—without needing manual file references. This makes it excellent for tasks like:
- Code Generation: Sonnet 4 produces clean, production-ready code in Python, JavaScript, Node.js, and more. It handles complex logic, such as writing CRUD APIs for Firebase or optimizing Pandas scripts, with fewer hallucinations than earlier models.
- Refactoring and Debugging: Highlight a messy function, and Cascade suggests streamlined rewrites or catches subtle bugs. Sonnet 4’s reasoning reduces navigation errors to near zero, a leap from Sonnet 3.7’s 20% error rate.
- Automation: Cascade can execute terminal commands (with user approval) and write files autonomously, saving time on repetitive tasks like setting up CI/CD pipelines.
The user experience is smooth, with features like Tab to Jump (predicting your next edit) and Supercomplete (context-aware autocomplete) enhancing workflows. Windsurf’s interface feels lightweight yet powerful, with a revamped Turbo Mode that auto-executes commands unless explicitly denied. However, some developers note occasional struggles with niche tasks, like conditional formatting in React Native, where Sonnet 4 may require multiple prompts to get it right.
Token Usage in Windsurf
Token usage is a critical consideration, as Claude Sonnet 4’s advanced capabilities come with a cost. Windsurf uses a credit-based system, where each Cascade request consumes credits based on token processing. Here’s how it works:
- Pricing Structure: Claude Sonnet 4 is available at 2x credits per request for Pro and Teams users (a limited-time discount from July 2025), equating to about 250 requests per month on a $15 Pro plan. Each request includes input and output tokens, with prompt cache writes costing an extra 25% for input tokens.
- Token Consumption: A single request, like generating a function or refactoring code, can consume hundreds of tokens depending on context length and complexity. For example, a three-hour refactoring session with Sonnet 4 burned through $90 in API costs for one user, highlighting the high token usage for intensive tasks.
- Thinking Mode: Sonnet 4’s extended thinking mode, which enables deeper reasoning, significantly increases token usage—sometimes 4x more than standard requests. Developers report that a single “thinking” prompt can eat 10-70 credits, making it pricey for casual use.
- BYOK Option: Windsurf supports Bring Your Own Key (BYOK) for Claude Sonnet 4, allowing users to input their Anthropic API key. This can be costlier, with reports of $50-$90 daily spends for heavy usage, as users pay Anthropic’s per-token rates ($3/$15 per million input/output tokens) directly.
- Monitoring: Windsurf shows credit consumption by hovering over completed actions in Cascade, but some users wish for more real-time token tracking to avoid surprises.
Compared to alternatives like Cursor, Windsurf’s flat-rate pricing can be more predictable than per-token API costs, but heavy users may find BYOK expensive. For context, Sonnet 4’s 2x credit cost is higher than DeepSeek R1’s 0.5x credits but competitive with OpenAI’s o3 at 1x credit.
Strengths and Weaknesses
Strengths:
- Code Quality: Sonnet 4 delivers elegant, precise code, especially for Python and Node.js, with strong reasoning for algorithms and multi-file edits.
- Context Awareness: Its 200,000-token context window handles large codebases effortlessly, reducing manual file inputs.
- Integration: Windsurf’s Cascade agent and Turbo Mode streamline automation, from terminal commands to file writes.
- Community Buzz: Developers on X praise Windsurf’s UX and Sonnet 4’s reliability, especially post-Anthropic reconciliation in July 2025.
Weaknesses:
- Cost: Token usage can skyrocket with thinking mode or BYOK, with some users reporting $7.60 for a single Opus 4 task.
- Learning Curve: Setting up BYOK or managing context limits requires technical know-how, and occasional errors (e.g., 429 rate limit issues) disrupt workflows.
- Niche Tasks: Sonnet 4 struggles with specific tasks like React Native formatting, requiring manual intervention.
Is It Worth It?
Windsurf with Claude Sonnet 4 is a powerhouse for developers who value precision and automation. Its ability to navigate complex codebases and generate clean code makes it ideal for professional projects, especially in Python and JavaScript. The $15/month Pro plan offers good value for 250 Sonnet 4 requests, but heavy users should budget carefully—thinking mode and BYOK can drain credits fast. Compared to Cursor, which has native Claude 4 support, Windsurf’s agentic features and flat-rate pricing give it an edge for teams, though solo devs may prefer Cursor for simpler setups.
For cost-conscious coders, DeepSeek R1 remains a cheaper alternative, but Sonnet 4’s superior reasoning and context handling justify the premium for complex tasks. Monitor token usage closely, and consider sticking to standard mode for lighter work to stretch credits.
Final Thoughts
Windsurf with Claude Sonnet 4 delivers a vibrant, AI-driven coding experience that feels like pair programming with a genius. Its integration of Sonnet 4’s advanced reasoning and Windsurf’s Cascade agent makes it a top contender in 2025’s vibe-coding landscape. Just keep an eye on those tokens—great power comes with a cost, but for developers chasing efficiency and quality, it’s a price worth paying.
