Worker Mode for a Medusa Instance

In this document, you'll learn about the worker mode in Medusa and its importance in production.

What is a Worker?

Workers are processes running separately from the main application. They're useful for executing long-running or resource-heavy tasks in the background, such as importing products or updating a search index.

With a worker, these tasks are offloaded to a separate process. So, they won't affect the performance of the main application.

While workers are especially good for intensive tasks, it's recommended to always configuring a worker process in your setup if possible.

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Medusa Runtimes

Medusa has three runtime modes:

• server: the API Routes are registered, and no workers are started.
• worker: the API Routes aren't registered, and workers are started.
• shared: (default) the API routes are registered, and workers are started.

The runtime mode is configured by the worker_mode configuration in medusa-config.js.

For example:

medusa-config.js

const projectConfig = {
  // ...,
  database_url: "...",
  worker_mode: "worker",
}

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Usage in Production

When deploying the Medusa backend in production, it's recommended to deploy two instances:

1. One having the worker_mode configuration set to server.
2. Another having the worker_mode configuration set to worker.

In this case, it's best to set the worker_mode configuration's value to an environment variable, then set that environment variable differently for each deployed instance. For development, you can use shared as the environment variable's values.

Tip

Check out the Railway Deployment Guide as an example.