Quick answer

Cline is an open-source AI coding agent that runs inside VS Code. Instead of charging a subscription, you bring your own API key (Claude, GPT, Gemini, or local models via Ollama). Cline runs in Plan mode (think first) or Act mode (execute), asking for approval on each risky step. By 2026, it is the #1 open-source AI coding agent on GitHub.

Cursor, Claude Code, and Devin get the headlines, but Cline has quietly become one of the most-used AI coding tools in 2026 — especially among developers who already pay for an Anthropic API key. Here is what it is and why people are switching.

What is Cline?

Cline is a VS Code extension. Install it, paste in your API key (Claude, OpenAI, Gemini, OpenRouter, Bedrock, or local Ollama), and you have an agentic AI assistant inside your editor. Cline reads your code, plans changes, edits files, runs shell commands — all with your approval at each step.

How is it different from Cursor?

  • No subscription — Cline is free, you pay your API key directly
  • Open source (Apache 2.0) — fully auditable, no proprietary backend
  • Lives inside vanilla VS Code — keep your existing setup, extensions, themes
  • Plan/Act split — Cursor blurs them; Cline makes you explicit
  • BYO model — switch between Claude Opus, GPT-5, Gemini, local Llama freely

The Plan vs Act model

Cline's flagship UX choice: every task has a Planning phase and an Action phase. In Planning, Cline lays out what it intends to do — files it will edit, commands it will run, expected outcome. You read, refine, and then say "Act". This explicit separation prevents Cline from running off and doing 47 things you did not intend.

Pricing — bring your own key

No subscription. You pay your API provider directly. Realistic monthly costs:

  • Light use (a few hours/week): $5-15/month via Claude API
  • Daily use, moderate tasks: $30-70/month
  • Heavy use, agentic refactors: $100-200/month
  • Local models via Ollama: $0 — just electricity

The economics are dramatic for moderate users. Cursor charges $20/mo bundling model costs. With Cline at moderate usage you might pay $30-50/mo to your API provider directly — but you get any model you want, full transparency on costs, and an open-source tool you can fork.

What it is genuinely best at

  • Refactors across multiple files with clear scope
  • Bug fixes when you can describe symptoms clearly
  • Generating tests for existing code
  • API integration boilerplate
  • Repo-wide search and structured edits
  • Anyone who wants to use Claude Opus 4.7 for coding without paying for both Claude Pro and Cursor

What it is not great at

  • Inline autocomplete — Cline is task-oriented, not keystroke-oriented (use Copilot or Continue for that)
  • Lightning-fast simple edits — the planning step adds latency
  • Beginners — the explicit Plan/Act model has a learning curve

Who should switch to Cline?

Three groups. (1) Developers already paying for Claude Pro / Claude API — you are paying twice if you also subscribe to Cursor. (2) Teams that need auditability for AI-generated code (open source = inspectable). (3) Anyone uncomfortable with their AI coding tool routing code through a third party — Cline lets you use local Ollama models with zero data leaving your machine.

Pair it with Continue for the complete setup

Many developers run Cline (for agentic tasks) alongside Continue (for inline autocomplete). Both are free, both BYO API key. Total cost: whatever you spend on your API. This combination roughly matches Cursor functionality at zero subscription cost.

Related reading

Best AI Coding Agents in 2026 — Cursor, Devin, Cline Compared Cursor vs Windsurf vs Claude Code — Which AI Coder Wins in 2026? Is Devin Worth $500/mo? An Honest Review of the AI Software Engineer

Bottom line

Cline is the smart pick for developers who want full control — over their model choice, their costs, their data, and their tooling. It trades a bit of polish for a lot of flexibility. If you already have a Claude or GPT API key, it should be the first AI coding tool you try.