Junie vs OpenAI Codex (2026)

Junie

by JetBrains

OpenAI Codex

by OpenAI

Pros

• ✓Runs in the terminal on Linux, macOS and Windows, inside JetBrains IDEs and Android Studio, and in CI through a GitHub Action and GitLab CI/CD.
• ✓Works with any model: JetBrains AI cloud models, bring-your-own-key from OpenAI, Anthropic, Google, xAI, OpenRouter or GitHub Copilot, and local models.
• ✓Plan mode writes an editable plan before coding, and in JetBrains IDEs Junie can drive the debugger and inspect runtime state.

Limitations

• ⚠The free start includes 5 AI credits, and cloud use beyond them needs a JetBrains AI plan, a Junie API key or the developer's own provider keys.
• ⚠Junie Local requires an Apple Silicon M5 Mac with macOS 26 or later and 64 GB of RAM, and runs one fixed Qwen3.6-27B model for now.
• ⚠Remote mode needs a JetBrains Account or Junie API key sign-in, and is not available through JetBrains AI Enterprise.

Pros

• ✓One agent spans the ChatGPT desktop app, the open-source Codex CLI, IDE extensions for VS Code, Cursor and Windsurf, native Xcode and JetBrains integrations, and Codex cloud on the web and iOS.
• ✓Codex reviews GitHub pull requests and GitLab merge requests on request or automatically, and a GitHub Action, the Codex SDK and codex exec bring it into CI and scripted workflows.
• ✓Parallel tasks in separate worktrees, subagents, Skills, plugins, MCP servers and scheduled tasks let Codex take on longer and repeated work, with GPT-6 Sol and GPT-6 Luna on Plus and above.

Limitations

• ⚠Codex usage is metered against plan limits shared with ChatGPT Work, and the number of messages varies with the model, task size and context, so heavy users on Plus may need credits or a Pro plan.
• ⚠OpenAI removed the Codex MCP server on September 5, 2026, so other assistants can no longer call Codex over MCP, although Codex still connects out to external MCP servers.
• ⚠The Codex documentation covers GitHub and GitLab and does not mention Bitbucket, and Codex run with an API key excludes the cloud features such as GitHub code review and Slack.