Update (April 2026): The hot-reload plugin now supports ?local-disk-file=<path> for plugins exceeding IntelliJ’s 180 MB body limit. See My IntelliJ Plugin Hit HTTP 413 for the full story.

Restarting IntelliJ for every plugin tweak is a productivity tax. The wait breaks flow, and by the time the IDE is back up you’ve lost the tiny detail you were trying to test. I wanted a tighter loop, so I built intellij-plugin-hot-reload.

Series: Holiday Sprint with AI

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The Endpoint

The plugin registers a built-in server handler at:

/api/plugin-hot-reload

• GET returns a Markdown README packaged inside the plugin.
• POST accepts the raw plugin ZIP as the request body.

The handler is strict: it requires Authorization: Bearer <token> and rejects empty uploads. The token changes each IDE run, which keeps the endpoint local and short-lived.

Discovery and Auth

On startup, the plugin writes a marker file to the user home directory:

~/.<pid>.hot-reload

It contains the POST URL, the bearer token, a timestamp, and a full IDE “About” block. The file disappears on IDE exit and stale marker files are cleaned up automatically. The Gradle deployPlugin task scans these markers and pushes new ZIPs to running IDEs.

The Reload Pipeline

The reload flow is intentionally explicit:

1. Read the plugin ZIP and extract the plugin ID (supports nested JAR layouts).
2. Reject self-reload to avoid unloading the hot-reload plugin itself.
3. Unload the existing plugin via the dynamic plugin API.
4. Replace the plugin directory on disk.
5. Install and load the new plugin descriptor.

If unload fails, the service can capture an HPROF snapshot and returns restartRequired = true. The endpoint always finishes with a final SUCCESS or FAILED line so callers can automate around it.

The Fine Print

There are some intentional quirks:

• The response is chunked, but progress is buffered and sent once at the end (no streaming updates).
• Requests time out after 5 minutes; a timeout still returns FAILED.
• A short 5-second delay is added after reload to let background invocables finish.

This is experimental and intentionally tied to IntelliJ internals. It works, but it is not guaranteed to survive major IDE releases without updates.

If you want the code, it is here: github.com/jonnyzzz/intellij-plugin-hot-reload.

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