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JetBrains Fleet Review: The Lightweight IDE Experiment That Aimed to Challenge VS Code With JetBrains Intelligence

Historical Review (65/100): JetBrains Fleet was a distributed, polyglot lightweight editor built from scratch with native AI integration and cloud workspaces. Note: JetBrains officially discontinued Fleet on December 22, 2025.

reviewed by Raşit Akyol March 27, 2026

Documented evidence

rubric editorial-review-v1

This review is grounded in documented sources and repository analysis. It does not claim a unique hands-on reproducibility record.

Sources checked

Verdict

Historical Benchmark (65/100): JetBrains Fleet explored distributed editor architecture and lightweight AI workflows before JetBrains sunset the project on December 22, 2025 to concentrate on JetBrains AI Pro within its flagship IDE suite. Active modern lightweight and cloud-enabled editors include VS Code, Cursor, Zed, and GitHub Codespaces.

65/100

overall

Speed82
Privacy80
Dev Experience68

What JetBrains Fleet Was

JetBrains Fleet represented an ambitious experiment: could JetBrains build a lightweight editor that started as fast as VS Code but could activate full IntelliJ-grade code intelligence on demand? The answer was technically yes, but the market did not reward the effort. On December 8, 2025 JetBrains announced that Fleet would be discontinued on December 22, 2025, with the company refocusing its agentic development investment on a new product — code-named Air — built on the Fleet platform alongside its established IDE lineup of IntelliJ IDEA, PyCharm, WebStorm, and the rest of the family.

Dual-Mode Architecture and Collaboration

The core innovation was the dual-mode architecture. Fleet launched in a lightweight mode that provided fast editing, basic syntax highlighting, and file navigation — competitive with VS Code for quick file editing. Activating Smart Mode spun up the full JetBrains code analysis engine, providing the deep code intelligence, refactoring capabilities, and error detection that JetBrains IDEs are known for. The transition between modes was the technology challenge that Fleet aimed to solve.

Collaborative editing was built in from the start, enabling real-time multi-user editing similar to Google Docs. This positioned Fleet for remote team workflows where multiple developers work on the same codebase simultaneously. The collaboration features were technically solid and ahead of what most IDEs offered at the time.

Polyglot Support and Discontinuation

The polyglot architecture supported multiple languages in a single workspace without needing separate IDE products — a departure from JetBrains' traditional model of language-specific IDEs. This was appealing for full-stack developers who work across Python, JavaScript, Go, and other languages within the same project.

The discontinuation was a strategic decision rather than a technical failure. JetBrains concluded that investing AI capabilities into their existing IDEs — which already have millions of users, mature ecosystems, and deep language support — would deliver more value than building a new editor from scratch. The AI features that were developed for Fleet, including code generation and intelligent completion, were redirected to JetBrains AI Assistant across the established IDE lineup.

The Fleet Experience and Lessons Learned

For developers who tried Fleet during the preview, the experience was promising but incomplete. Performance was good in lightweight mode, and Smart Mode delivered the expected JetBrains code intelligence. The plugin ecosystem was limited compared to VS Code and established JetBrains IDEs, and some language support was still maturing. The collaborative features worked well but could not overcome the ecosystem gap.

The lesson from Fleet is instructive for the broader IDE market. Building a new editor requires not just good technology but an ecosystem of plugins, community support, and workflow integration that takes years to develop. VS Code's dominance is not just about the editor — it is about the thousands of extensions, the familiarity, and the integration with the broader development workflow. Cursor succeeded where Fleet did not partly because it forked VS Code's ecosystem rather than building from scratch.

JetBrains AI Today and Fleet's Legacy

For developers currently looking for a JetBrains experience with AI capabilities, two paths converge. The mainstream option is JetBrains AI Assistant integrated into IntelliJ, PyCharm, WebStorm, and other established JetBrains IDEs — providing code completion, chat, code explanation, and refactoring suggestions powered by multiple LLM providers. The forward-looking option is JetBrains Air, a new agentic development product in preview that inherits Fleet's platform and reframes it as an AI-first workflow rather than a general-purpose editor.

Fleet's technology contributions live on within the JetBrains ecosystem. The lightweight rendering engine, collaborative editing infrastructure, and polyglot architecture have influenced features in the main IDE products and now form the foundation of the Air preview. The experiment was valuable even though the standalone product did not survive — its successor reframes the same platform around agentic development rather than chasing VS Code on its own terms.

The Bottom Line

JetBrains Fleet in 2026 is a historical footnote in the AI IDE evolution. It demonstrated that building a competitive new editor from scratch is extraordinarily difficult even for a company with JetBrains' resources and developer tool expertise. The AI capabilities it pioneered are now available through JetBrains AI Assistant in the established IDE lineup and through JetBrains Air in preview — which is where JetBrains developers should focus their attention going forward.

Pros

  • Dual-mode architecture delivered VS Code speed with JetBrains code intelligence on demand
  • Built-in collaborative editing enabled real-time multi-user development
  • Polyglot architecture supported multiple languages in a single workspace
  • Technology contributions influenced AI features in established JetBrains IDEs
  • Lightweight mode was genuinely fast for quick file editing and navigation
  • Smart Mode provided full JetBrains-grade refactoring and error detection
  • Free during public preview provided risk-free evaluation

Cons

  • Discontinued in 2025 — no longer actively developed or supported
  • Plugin ecosystem was limited compared to VS Code and established JetBrains IDEs
  • Building a new editor ecosystem from scratch proved too difficult even for JetBrains
  • Language support was still maturing for some languages during the preview period
  • Users must migrate to established JetBrains IDEs for continued AI-powered development

View JetBrains Fleet on aicoolies

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FAQ

How does Fleet's distributed architecture separate UI from intelligence?

Splits into a Kotlin Multiplatform Skia frontend, an in-memory Workspace engine, and an on-demand IntelliJ headless backend daemon parsing full PSI ASTs without blocking UI threads.

What are the performance and memory trade-offs of Fleet's Smart Mode?

Launches in under 500ms (150–250MB RAM) with basic TextMate grammars; Smart Mode spins up headless JVM IntelliJ engines (1.2–2.5GB RAM) for deep type inference and AST refactoring.

How does Fleet's remote protocol compare to VS Code Remote?

Synchronizes document buffers and workspace states asynchronously over encrypted RPC streams, maintaining sub-16ms local typing latency regardless of network jitter to remote servers.

Why was Fleet discontinued, and what survived in JetBrains?

Sunset in late 2025 due to plugin ecosystem headwinds; core innovations (Kotlin Multiplatform UI, Skia rendering, headless daemon protocols) were upstreamed into main IntelliJ IDEs.

Sources & verification

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