JetBrains Air vs OpenAI Codex App: Which AI Coding Tool Really Wins?

JetBrains Air Overview

In March 2026 JetBrains released Air, an "Agentic Development Environment" that can manage multiple AI agents concurrently in isolated environments such as local workspaces, Git worktrees, and Docker containers.

Air supports OpenAI Codex, Anthropic Claude, Google Gemini, and JetBrains' own Junie, allowing developers to switch models within a single project and avoid vendor lock‑in. Integration is possible via the Agent Client Protocol (ACP) co‑developed with Zed.

Local Workspace – runs directly on the developer’s machine.

Git Worktree – creates a separate branch for each task.

Docker Container – provides a fully sandboxed environment.

OpenAI Codex App

Released in February 2026, the Codex desktop app follows a closed‑ecosystem approach, supporting only OpenAI’s GPT‑5.4 model.

Its main advantage is efficiency: token consumption is lower and response speed higher, giving roughly double the coding output for the same ChatGPT Plus/Pro subscription cost.

For existing ChatGPT Plus users the Codex app is free, requiring no additional subscription.

Cost and Subscription Comparison

JetBrains Air requires a separate JetBrains AI subscription, plus additional API keys for Claude or Gemini, making it an extra expense.

By contrast, Codex App leverages the existing ChatGPT subscription, offering a zero‑cost solution for developers already on that plan.

Background: Fleet’s Failure and Air’s Foundations

"Air inherits parts of Fleet for agentic workflows."

JetBrains discontinued its Fleet IDE in December 2025, repurposing its codebase for Air, which raises concerns about the product’s long‑term viability.

Air is currently macOS‑only, with Windows and Linux versions still pending.

Market Landscape

Other AI‑assisted coding tools have emerged rapidly: Cursor (2024), Anthropic’s Claude Code (2025), and the third‑generation GitHub Copilot (2026). These competitors offer native AI editing experiences and have captured significant developer interest.

Practical Advice for Developers

The author recommends skipping both desktop apps and using terminal‑based CLIs instead.

Commands such as codex or claude can be run directly in the terminal, providing a lightweight, flexible workflow without the overhead of GUI applications.

Switch between Codex and Claude Code as needed.

Assign different tools to different projects.

Avoid lock‑in to any single desktop environment.

Desktop apps essentially add a graphical layer on top of the terminal, offering nicer interfaces but no fundamental advantage.

Conclusion

While JetBrains Air presents a clean UI and solid isolation features, its late arrival, limited platform support, and additional cost make it a less compelling choice compared to the free, efficient Codex App for existing ChatGPT users. Ultimately, the terminal remains the most versatile tool for AI‑assisted development.