Platform projects consist of ordinary Git repositories, so you can work on them with IntelliJ IDEA and other JetBrains IDEs. The platform integration is leaner here than in Cursor, VS Code and Antigravity: there is no extension with a welcome page and start buttons, and you set up project configuration in the IDE yourself.
What the platform provides
The setup app can install IntelliJ IDEA during developer setup and open projects in it with one click if you choose it as the default tool there. The project folder contains an .idea directory, symlinked from local-configuration, which serves as the shared place for team settings. In JetBrains, open the parent project folder under ~/Documents/application-platform/<organization-slug>/<project-slug> with all repositories, so backend, app and configuration sit in one window.
What you set up yourself
Run configurations, SDK assignment and module structure are created in the IDE; the platform does not generate them. You start applications in the IDE terminal inside the respective repository with the ap CLI:
ap run-local
Runtime versions come from the repository’s .tool-versions; when the IDE asks for an SDK, pick the version listed there so that local builds and the pipeline match.
AI assistant in JetBrains
The generated rule files AGENTS.md, CLAUDE.md and .cursor/rules are tailored to Claude Code, Codex, Cursor and Antigravity. If you use the JetBrains AI Assistant, point it to the AGENTS.md in the project folder in your prompt or in its settings so that it knows the same platform rules. You can start Claude Code and Codex independently of the IDE in the terminal of the project folder; they read the rules on their own. How to extend the rules with your own instructions is described in Your own rules for AI agents.