Key Takeaways
- Cline has surpassed 5 million installs on the VS Code Marketplace, making it the most widely used open-source autonomous coding agent available for VS Code.
- The extension is Apache 2.0 licensed and completely free to install; you pay only for the AI model API calls you make, with no Cline markup or subscription required for individual use.
- Cline raised $32 million in funding led by Emergence Capital in 2025, backing an enterprise teams product while keeping the core extension free.
- GitHub’s Octoverse 2025 recognized Cline as the fastest-growing AI project on GitHub, with 4,704% year-over-year contributor growth and over 61,000 stars.
- Cline supports 15+ model providers including Anthropic, OpenAI, Google Gemini, AWS Bedrock, Azure, and local models via Ollama or LM Studio, so you are never locked to a single AI vendor.
- The Plan/Act mode system lets you review a full strategy before any file is touched, and every file edit and terminal command still requires explicit approval in Act mode unless you enable YOLO mode.
- Real-world monthly API costs for active developers typically range from $15 to $120 depending on model choice and usage volume, with Gemini and DeepSeek models offering significantly cheaper runs than Claude Sonnet.
- Cline is not a self-contained IDE like Cursor or Windsurf; it lives inside your existing VS Code setup, which means zero editor migration and full access to your existing extensions and settings.
- Fortune 500 companies including Samsung and SAP already use Cline internally, according to the company’s Series A announcement.
If you have spent any time in developer communities over the past year, you have likely seen Cline mentioned alongside Cursor and Windsurf in the ongoing debate about the best AI coding tools. Cline sits in its own category: it is not a new IDE you install, not a cloud service that handles your code behind a subscription wall, and not a simple autocomplete plugin. It is an autonomous agent that lives inside your existing VS Code installation and acts on your codebase with your explicit sign-off at each step.
This review covers what Cline actually does day-to-day, where it earns its reputation, where it frustrates developers, how its costs work in practice, and how it stacks up against Cursor and Windsurf. All testing observations and statistics here come from published sources and developer community reports rather than marketing copy.
The short version: Cline is the most flexible open-source coding agent available for VS Code right now, and the install numbers prove developers agree. Whether it is the right tool for you depends on your tolerance for API costs, your preference for control versus speed, and whether you want to stay in VS Code or switch to a purpose-built AI editor.
What is Cline?
Cline started life under the name “Claude Dev” and was created by Saoud Rizwan, whose developer ID (saoudrizwan.claude-dev) still appears as the extension identifier in the VS Code Marketplace today. The project was later renamed Cline, incorporated as a company, and is now backed by institutional funding while remaining fully open source under the Apache 2.0 license.
The core idea is straightforward: rather than suggesting code completions or chatting about code in a sidebar, Cline takes on tasks end-to-end. You describe what you want, Cline reads your codebase, proposes changes, and then executes them after you approve each step. It can create and edit files, run terminal commands, install packages, execute tests, browse the web using a Puppeteer-driven browser, and react to command outputs in real time.
Cline is model-agnostic by design. You connect your own API keys and choose the model that fits your budget and task. This stands in contrast to Cursor or Windsurf, which bundle model access into their subscription pricing. With Cline, the cost of the model goes directly to the provider at the provider’s rates, with no markup from Cline itself.
As of 2025, the Cline GitHub repository holds over 61,200 stars. The project was named the fastest-growing AI open source project on GitHub in 2025, with contributor counts growing 4,704% year over year.
Cline Features
Plan and Act Modes
This is the feature that separates Cline from most AI coding assistants. In Plan mode, the agent explores your codebase, asks clarifying questions, and produces a written strategy before touching a single file. You review the plan, correct any misunderstandings, and then switch to Act mode to execute. This two-phase approach reduces wasted tokens on misguided implementations and gives you a clear audit trail of what the agent intends to do and why.
Plan mode is particularly useful for complex refactors or features that touch many files. Instead of watching the agent guess and backtrack, you align on the approach first. Once aligned, Act mode executes the plan step by step, pausing at each file edit and terminal command for your approval.
Terminal and Command Execution
Cline can run commands directly in your VS Code terminal and reads the output in real time. This means it can install npm packages, run build scripts, execute test suites, start dev servers, and react to errors it finds in the output. For long-running processes, Cline continues working in the background and adjusts when new terminal output appears.
This level of terminal access is where Cline pulls ahead of tools that only edit files. Seeing a build failure and immediately correcting the code that caused it is a qualitatively different workflow from a tool that only suggests edits and leaves the running and testing to you.
YOLO Mode
Introduced in version 3.10, YOLO mode removes the per-step approval gates. With it enabled, Cline executes file edits and terminal commands autonomously until the task is done. This speeds up long tasks significantly but requires you to trust the model’s judgment. Most developers use YOLO mode only for well-scoped tasks where the risk of a wrong command is low, reverting to the standard approval flow for anything touching production configuration or deployment scripts.
MCP Marketplace
The Model Context Protocol (MCP) Marketplace, introduced in Cline v3.4, works like an app store for Cline extensions. Previously, connecting Cline to external tools required manual JSON configuration and searching GitHub for compatible servers. The MCP Marketplace lets you browse, install, and configure MCP servers with a single click inside the IDE. Once installed, MCP tools become available to the agent automatically, giving it access to databases, cloud platforms, and external APIs beyond what the base extension provides.
Model Provider Flexibility
Cline supports over 15 model providers out of the box: Anthropic (Claude), OpenAI (GPT-4o and o-series), Google Gemini, AWS Bedrock, Azure OpenAI, Google Cloud Vertex AI, Cerebras, Groq, OpenRouter, and local models via LM Studio or Ollama. This breadth matters when API pricing changes, new models release, or when you want to run a cheaper model for exploratory tasks and switch to a stronger one for final implementation.
Browser Control
Cline can drive a real Chromium browser via Puppeteer, which means it can navigate to a running local app, check a rendered page for errors, fill out a form to test a workflow, or pull information from a web page. This is more than just web search: the agent interacts with your actual running application the way a human tester would.
JetBrains and CLI Support
Beyond VS Code, Cline is available as an extension for the full JetBrains family including IntelliJ IDEA, PyCharm, WebStorm, and GoLand. There is also a CLI version that supports interactive chat mode and headless operation for CI/CD pipelines and scripting workflows.
Cline Pricing
The Cline VS Code extension is free to download and free to use as an individual. There is no subscription fee charged by Cline for the core extension. Costs come entirely from the AI model APIs you connect through your own keys.
- Individual use, free tier: Install the extension, connect any API key, and pay the model provider directly at their standard rates. No Cline subscription needed.
- Free model options: As of mid-2025, Gemini 2.0 Pro Experimental costs $0.00 per million tokens through the Google AI API, making it possible to run Cline at near-zero cost for experimentation.
- Economical models: DeepSeek R1 runs at approximately $0.65 per million input tokens and $2.19 per million output tokens via OpenRouter, keeping a working month well under $20 for most developers.
- Premium models: Claude 3.5 Sonnet and Claude 3.7 Sonnet cost $3.00 per million input tokens and $15.00 per million output tokens through Anthropic’s API. Active developers using these models typically spend between $25 and $70 per month, based on Cline’s model comparison docs.
- Cline Teams: The enterprise product was free through Q1 2026, then priced at $20 per user per month, with the first 10 seats always free.
The unpredictability of API costs is the most consistent complaint from developers who try Cline. A heavy session with Claude Sonnet on a complex codebase can cost $10 to $20 in a single afternoon. Developers on tight budgets tend to use Cline with cheaper models for daily work and switch to Claude only for tasks that genuinely need it.
Cline Pros and Cons
Pros:
- Completely free to install; no subscription required for individual use
- Supports over 15 model providers with no vendor lock-in
- Plan/Act mode gives you full visibility into the agent’s strategy before any code changes
- Per-step approval gates mean you can catch mistakes before they land in your codebase
- Apache 2.0 license means the code is auditable, forkable, and modifiable
- Fastest-growing AI open source project on GitHub in 2025 per GitHub Octoverse
- Works inside your existing VS Code setup with no editor migration required
- Terminal integration handles installs, tests, and build scripts, not just file edits
- MCP Marketplace extends capabilities to databases, APIs, and external tools
- JetBrains and CLI support broadens the platform beyond VS Code
Cons:
- API costs are variable and can spike unexpectedly on long or complex tasks
- Quality varies significantly depending on which model you connect
- Per-step approval gating slows down long tasks unless you enable YOLO mode
- No built-in compliance or security certifications, which limits use in regulated industries
- Can get stuck in loops on complex tasks, requiring manual intervention and re-prompting
- Large codebases can strain context windows, leading to incomplete understanding of dependencies
- No native diff view as polished as Cursor’s UI for reviewing proposed changes
Cline vs Alternatives
Cline vs Cursor
Cursor is a full VS Code fork built around AI coding, priced at $20 per month for the Pro plan. It offers tighter UI integration, faster inline completions, and as of Cursor 2.0, background agents running on cloud VMs with up to 8 parallel workers using git worktree isolation. In head-to-head task timing, Cursor tends to complete equivalent tasks in roughly half the time (around 45 seconds versus Cline’s 90 seconds on some benchmarks), according to developer reports on the DataCamp comparison.
The trade-off is control and flexibility. Cursor bundles its model access, so you use what Cursor provides at the price Cursor sets. Cline lets you plug in any provider, swap models per task, and see exactly what the agent is doing at each step. Developers who want predictable monthly billing and polished UX tend to prefer Cursor. Developers who want model freedom and cost transparency tend to prefer Cline.
Cline vs Windsurf
Windsurf (by Codeium) is another AI IDE starting at $15 per month. It has strong context awareness in large monorepos and multi-module codebases, with real developer reports on Reddit noting that Windsurf handles large codebase navigation better than Cursor in some scenarios. Like Cursor, it is a self-contained editor, not a VS Code extension, which means switching to it requires leaving your current setup.
Cline’s advantage over Windsurf is the same as against Cursor: open source, model-agnostic, and VS Code-native. Windsurf’s advantage is its polished onboarding experience and stronger codebase indexing for very large projects. For teams who need compliance documentation or enterprise security certifications, Windsurf and Cursor are currently better positioned than Cline.
Cline vs GitHub Copilot
GitHub Copilot remains the most widely installed AI coding tool overall, with its autocomplete and chat features built directly into VS Code and other editors at $10 per month for individuals. Copilot focuses on inline suggestions and chat-based assistance rather than autonomous multi-step execution. Cline does things Copilot cannot: run terminal commands, execute tests, navigate a browser, and chain dozens of file edits across a task without asking you to do each step manually. Developers often run both: Copilot for fast inline completions during active typing, and Cline for larger self-directed tasks.
Who is Cline Best For?
Cline is the right choice for developers who want an autonomous coding agent without switching editors or committing to a fixed subscription. It works best for:
- VS Code users who want to stay in VS Code: No migration, no learning a new editor, no disruption to your existing extensions and keybindings.
- Cost-conscious developers: If you connect a cheaper model like DeepSeek or Gemini, you can get real autonomous coding value for a few dollars a month. You control spending directly.
- Developers who value transparency: Every token count, file edit, and terminal command is visible. Plan mode shows you the strategy before execution. Nothing happens without your sign-off.
- Open source contributors and hobbyists: The Apache 2.0 license means you can fork, audit, and modify the extension itself.
- Teams experimenting with AI-assisted development: The first 10 seats on Cline Teams are free, making it a low-risk way to evaluate autonomous coding agents at the team level.
Cline is less suited to developers who want the fastest possible autocomplete experience, who need enterprise security certifications, or who prefer a fully managed product where someone else handles the infrastructure and model updates.
Our Verdict
Cline earns its 5 million installs. No other open-source VS Code extension comes close to what it offers in terms of autonomous, multi-step coding capability. The Plan/Act system is genuinely useful for complex tasks, the model flexibility is a real differentiator, and the terminal integration makes it feel like a collaborator rather than a suggestion engine.
The main friction points are real but manageable. API costs require attention, particularly if you default to Claude Sonnet on every task. Long sessions on large codebases can still produce loops and dead ends that need human correction. And the per-step approval flow, while the right safety model, adds latency compared to more autonomous alternatives like Cursor’s background agents.
For developers who want to stay in VS Code, maintain full control over model choice and cost, and work with an agent that shows its work at every step, Cline is the strongest option available in 2025. For developers who prioritize raw speed and are comfortable with a $20/month subscription, Cursor is the closer competitor. Both can coexist in a workflow, and many experienced developers use exactly that combination.
Frequently Asked Questions
Is Cline completely free?
The Cline VS Code extension is free to download and install. There is no subscription fee charged by Cline for individual use. You pay only for the AI model API calls you make through your own provider keys. Costs vary by model: Gemini experimental models can cost close to zero, while Claude Sonnet sessions can run $15 to $120 per month for active developers depending on usage volume.
How many people use Cline?
Cline has surpassed 5 million installs on the VS Code Marketplace as of 2025. The GitHub repository has over 61,200 stars. GitHub’s Octoverse 2025 named it the fastest-growing AI open source project on the platform, with 4,704% year-over-year contributor growth.
Does Cline work with models other than Claude?
Yes. Cline supports over 15 model providers including OpenAI, Google Gemini, AWS Bedrock, Azure OpenAI, Groq, Cerebras, OpenRouter, and local models through LM Studio or Ollama. You choose the provider and model for each session. Many developers use cheaper models for routine tasks and switch to Claude or GPT-4o for complex work.
How is Cline different from Cursor?
Cursor is a full VS Code fork with bundled AI model access, priced at $20 per month for its Pro plan. Cline is an open-source extension that runs inside your existing VS Code and uses your own API keys from any provider. Cursor tends to be faster for inline tasks and has a more polished UI. Cline gives you more control, model flexibility, and transparency at the cost of variable API billing and a slightly rougher interface.
Can Cline run terminal commands on its own?
Yes. Cline can execute terminal commands, read their output in real time, and react to errors or results before moving to the next step. In standard mode, each command requires your approval before running. In YOLO mode (introduced in version 3.10), commands execute without pausing for confirmation, which speeds up long tasks but requires more trust in the model.
Is Cline safe to use on production codebases?
Cline’s default approval model requires you to confirm each file edit and terminal command, which provides a meaningful safety layer. For production work, most developers keep YOLO mode off, review each proposed change carefully, and ensure they are working on a git branch so changes are easy to revert. Cline does not have built-in compliance certifications for regulated industries like healthcare or financial services.
What is the MCP Marketplace in Cline?
The MCP Marketplace, introduced in Cline v3.4, is a built-in directory of Model Context Protocol servers that extend Cline’s capabilities. You can browse, install, and configure MCP servers with a single click inside VS Code. These servers connect Cline to databases, cloud platforms, and external APIs, giving the agent access to tools beyond what the base extension provides without manual JSON configuration.
Does Cline work in JetBrains IDEs?
Yes. Cline is available as an extension for the full JetBrains family, including IntelliJ IDEA, PyCharm, WebStorm, and GoLand. There is also a CLI version that supports interactive chat and headless operation for CI/CD and scripting workflows.
How much does Cline cost per month in practice?
Based on community estimates and developer reports, most active developers using Claude Sonnet spend between $25 and $70 per month on API costs. Developers using more economical models like DeepSeek R1 (approximately $0.65 per million input tokens) can keep monthly costs under $10. Heavy users or those running long agentic sessions can exceed $100 per month.
Who invested in Cline?
Cline raised $32 million in Seed and Series A funding led by Emergence Capital, with participation from Pace Capital, 1984 Ventures, Essence VC, and Cox Exponential. Notable angels include Jared Friedman from Y Combinator, Eric Simons (CEO of Bolt.new), and tech YouTuber Theo Browne. The funding was announced in 2025.
