Configure Medusa Backend

In this document, you’ll learn how to create a file service in the Medusa backend and the methods you must implement in it.

Prerequisites

This document assumes you already followed along with the Prepare Environment documentation and have a Medusa backend installed.

The configurations for your Medusa backend are in medusa-config.js located in the root of your Medusa project. The configurations include database, modules, and plugin configurations, among other configurations.

medusa-config.js exports an object having the following properties:

projectConfig: (required): An object that holds general configurations related to the Medusa backend, such as database or CORS configurations.
plugins: An array of plugin configurations that defines what plugins are installed and optionally specifies each of their configurations.
modules: An object that defines what modules are installed and optionally specifies each of their configurations.
featureFlags: An object that enables or disables features guarded by a feature flag.

For example:

medusa-config.js

module.exports = {
  projectConfig,
  plugins,
  modules,
  featureFlags,
}

Environment Variables

It's highly recommended to store the values of configurations in environment variables, then reference them within medusa-config.js.

During development, you can set your environment variables in the .env file at the root of your Medusa backend project. In production, setting the environment variables depends on the hosting provider.

projectConfig

This property holds essential configurations related to the Medusa backend, such as database and CORS configurations.

store_cors

The Medusa backend’s API Routes are protected by Cross-Origin Resource Sharing (CORS). So, only allowed URLs or URLs matching a specified pattern can send requests to the backend’s API Routes.

store_cors is a string used to specify the accepted URLs or patterns for store API Routes. It can either be one accepted origin, or a comma-separated list of accepted origins.

Every origin in that list must either be:

A URL. For example, http://localhost:8000. The URL must not end with a backslash;
Or a regular expression pattern that can match more than one origin. For example, .example.com. The regex pattern that the backend tests for is ^([/~@;%#'])(.*?)\1([gimsuy]*)$.

Example

Some example values of common use cases:

# Allow different ports locally starting with 800
STORE_CORS=/http://localhost:800\d+$/

# Allow any origin ending with vercel.app. For example, storefront.vercel.app
STORE_CORS=/vercel\.app$/

# Allow all HTTP requests
STORE_CORS=/http://.+/

Then, set the configuration in medusa-config.js:

medusa-config.js

module.exports = {
  projectConfig: {
    store_cors: process.env.STORE_CORS,
    // ...
  },
  // ...
}

If you’re adding the value directly within medusa-config.js, make sure to add an extra escaping / for every backslash in the pattern. For example:

medusa-config.js

module.exports = {
  projectConfig: {
    store_cors: "/vercel\\.app$/",
    // ...
  },
  // ...
}

admin_cors

The Medusa backend’s API Routes are protected by Cross-Origin Resource Sharing (CORS). So, only allowed URLs or URLs matching a specified pattern can send requests to the backend’s API Routes.

admin_cors is a string used to specify the accepted URLs or patterns for admin API Routes. It can either be one accepted origin, or a comma-separated list of accepted origins.

Every origin in that list must either be:

A URL. For example, http://localhost:7001. The URL must not end with a backslash;
Or a regular expression pattern that can match more than one origin. For example, .example.com. The regex pattern that the backend tests for is ^([/~@;%#'])(.*?)\1([gimsuy]*)$.

Example

Some example values of common use cases:

# Allow different ports locally starting with 700
ADMIN_CORS=/http://localhost:700\d+$/

# Allow any origin ending with vercel.app. For example, admin.vercel.app
ADMIN_CORS=/vercel\.app$/

# Allow all HTTP requests
ADMIN_CORS=/http://.+/

Then, set the configuration in medusa-config.js:

medusa-config.js

module.exports = {
  projectConfig: {
    admin_cors: process.env.ADMIN_CORS,
    // ...
  },
  // ...
}

If you’re adding the value directly within medusa-config.js, make sure to add an extra escaping / for every backslash in the pattern. For example:

medusa-config.js

module.exports = {
  projectConfig: {
    admin_cors: "/http:\\/\\/localhost:700\\d+$/",
    // ...
  },
  // ...
}

cookie_secret

A random string used to create cookie tokens. Although this configuration option is not required, it’s highly recommended to set it for better security.

In a development environment, if this option is not set, the default secret is supersecret However, in production, if this configuration is not set, an error is thrown and the backend crashes.

Example

medusa-config.js

module.exports = {
  projectConfig: {
    cookie_secret: process.env.COOKIE_SECRET ||
      "supersecret",
    // ...
  },
  // ...
}

jwt_secret

A random string used to create authentication tokens. Although this configuration option is not required, it’s highly recommended to set it for better security.

In a development environment, if this option is not set the default secret is supersecret However, in production, if this configuration is not set an error, an error is thrown and the backend crashes.

Example

medusa-config.js

module.exports = {
  projectConfig: {
    jwt_secret: process.env.JWT_SECRET ||
      "supersecret",
    // ...
  },
  // ...
}

database_database

The name of the database to connect to. If specified in database_url, then it’s not required to include it.

Make sure to create the PostgreSQL database before using it. You can check how to create a database in PostgreSQL's documentation.

Example

medusa-config.js

module.exports = {
  projectConfig: {
    database_database: process.env.DATABASE_DATABASE || 
      "medusa-store",
    // ...
  },
  // ...
}

database_url

The connection URL of the database. The format of the connection URL for PostgreSQL is:

postgres://[user][:password]@[host][:port]/[dbname]

Where:

[user]: (required) your PostgreSQL username. If not specified, the system's username is used by default. The database user that you use must have create privileges. If you're using the postgres superuser, then it should have these privileges by default. Otherwise, make sure to grant your user create privileges. You can learn how to do that in PostgreSQL's documentation.
[:password]: an optional password for the user. When provided, make sure to put : before the password.
[host]: (required) your PostgreSQL host. When run locally, it should be localhost.
[:post]: an optional port that the PostgreSQL server is listening on. By default, it's 5432. When provided, make sure to put : before the port.
[dbname]: (required) the name of the database.

You can learn more about the connection URL format in PostgreSQL’s documentation.

Example

For example, set the following database URL in your environment variables:

DATABASE_URL=postgres://postgres@localhost/medusa-store

Then, use the value in medusa-config.js:

medusa-config.js

module.exports = {
  projectConfig: {
    database_url: process.env.DATABASE_URL,
    // ...
  },
  // ...
}

database_schema

The database schema to connect to. This is not required to provide if you’re using the default schema, which is public.

medusa-config.js

module.exports = {
  projectConfig: {
    database_schema: process.env.DATABASE_SCHEMA || 
      "custom",
    // ...
  },
  // ...
}

database_logging

This configuration specifies what database messages to log. Its value can be one of the following:

(default) A boolean value that indicates whether any messages should be logged.
The string value all that indicates all types of messages should be logged.
An array of log-level strings to indicate which type of messages to show in the logs. The strings can be query, schema, error, warn, info, log, or migration. Refer to Typeorm’s documentation for more details on what each of these values means.

If this configuration isn't set, its default value is false, meaning no database messages are logged.

Example

medusa-config.js

module.exports = {
  projectConfig: {
    database_logging: [
      "query", "error",
    ],
    // ...
  },
  // ...
}

database_extra

An object that includes additional configurations to pass to the database connection. You can pass any configuration. One defined configuration to pass is ssl which enables support for TLS/SSL connections.

This is useful for production databases, which can be supported by setting the rejectUnauthorized attribute of ssl object to false. During development, it’s recommended not to pass this option.

Example

medusa-config.js

module.exports = {
  projectConfig: {
    database_extra: 
      process.env.NODE_ENV !== "development"
        ? { ssl: { rejectUnauthorized: false } }
        : {},
    // ...
  },
  // ...
}

Properties

sslobjectRequired

Configure support for TLS/SSL connection

redis_url

Used to specify the URL to connect to Redis. This is only used for scheduled jobs. If you omit this configuration, scheduled jobs won't work.

Note

You must first have Redis installed. You can refer to Redis's installation guide.

The Redis connection URL has the following format:

redis[s]://[[username][:password]@][host][:port][/db-number]

For a local Redis installation, the connection URL should be redis://localhost:6379 unless you’ve made any changes to the Redis configuration during installation.

Example

medusa-config.js

module.exports = {
  projectConfig: {
    redis_url: process.env.REDIS_URL || 
      "redis://localhost:6379",
    // ...
  },
  // ...
}

redis_prefix

The prefix set on all keys stored in Redis. The default value is sess:.

If this configuration option is provided, it is prepended to sess:.

Example

medusa-config.js

module.exports = {
  projectConfig: {
    redis_prefix: process.env.REDIS_PREFIX || 
      "medusa:",
    // ...
  },
  // ...
}

redis_options

An object of options to pass ioredis. You can refer to ioredis’s RedisOptions documentation for the list of available options.

Example

medusa-config.js

module.exports = {
  projectConfig: {
    redis_options: {
      connectionName: process.env.REDIS_CONNECTION_NAME || 
        "medusa",
    },
    // ...
  },
  // ...
}

session_options

An object of options to pass to express-session.

Example

medusa-config.js

module.exports = {
  projectConfig: {
    session_options: {
      name: process.env.SESSION_NAME || 
        "custom",
    },
    // ...
  },
  // ...
}

Properties

namestring

The name of the session ID cookie to set in the response (and read from in the request). The default value is connect.sid. Refer to express-session’s documentation for more details.

resaveboolean

Whether the session should be saved back to the session store, even if the session was never modified during the request. The default value is true. Refer to express-session’s documentation for more details.

rollingboolean

Whether the session identifier cookie should be force-set on every response. The default value is false. Refer to express-session’s documentation for more details.

saveUninitializedboolean

Whether a session that is "uninitialized" is forced to be saved to the store. The default value is true. Refer to express-session’s documentation for more details.

secretstring

The secret to sign the session ID cookie. By default, the value of cookie_secret is used. Refer to express-session’s documentation for details.

ttlnumber

Used when calculating the Expires Set-Cookie attribute of cookies. By default, its value is 10 * 60 * 60 * 1000. Refer to express-session’s documentation for details.

http_compression

Configure HTTP compression from the application layer. If you have access to the HTTP server, the recommended approach would be to enable it there. However, some platforms don't offer access to the HTTP layer and in those cases, this is a good alternative.

Its value is an object that has the following properties:

If you enable HTTP compression and you want to disable it for specific API Routes, you can pass in the request header "x-no-compression": true.

Example

medusa-config.js

module.exports = {
  projectConfig: {
    http_compression: {
      enabled: true,
      level: 6,
      memLevel: 8,
      threshold: 1024,
    },
    // ...
  },
  // ...
}

Properties

enabledboolean

Whether HTTP compression is enabled. By default, it's false.

levelnumber

The level of zlib compression to apply to responses. A higher level will result in better compression but will take longer to complete. A lower level will result in less compression but will be much faster. The default value is 6.

memLevelnumber

How much memory should be allocated to the internal compression state. It's an integer in the range of 1 (minimum level) and 9 (maximum level). The default value is 8.

thresholdstring | number

The minimum response body size that compression is applied on. Its value can be the number of bytes or any string accepted by the bytes module. The default value is 1024.

jobs_batch_size

Configure the number of staged jobs that are polled from the database. Default is 1000.

Example

medusa-config.js

module.exports = {
  projectConfig: {
    jobs_batch_size: 100
    // ...
  },
  // ...
}

plugins

On your Medusa backend, you can use Plugins to add custom features or integrate third-party services. For example, installing a plugin to use Stripe as a payment processor.

Aside from installing the plugin with NPM, you need to pass the plugin you installed into the plugins array defined in medusa-config.js.

The items in the array can either be:

A string, which is the name of the plugin to add. You can pass a plugin as a string if it doesn’t require any configurations.
An object having the following properties:
- resolve: The name of the plugin.
- options: An object that includes the plugin’s options. These options vary for each plugin, and you should refer to the plugin’s documentation for available options.

Example

medusa-config.js

module.exports = {
  plugins: [
    `medusa-my-plugin-1`,
    {
      resolve: `medusa-my-plugin`,
      options: {
        apiKey: process.env.MY_API_KEY || 
          `test`,
      },
    },
    // ...
  ],
  // ...
}

modules

In Medusa, commerce and core logic are modularized to allow developers to extend or replace certain modules with custom implementations.

Aside from installing the module with NPM, you must add it to the exported object in medusa-config.js.

The keys of the modules configuration object refer to the type of module. Its value can be one of the following:

A boolean value indicating whether the module type is enabled;
Or a string value indicating the name of the module to be used for the module type. This can be used if the module does not require any options;
Or an object having the following properties, but typically you would mainly use the resolve and options properties only:
1. resolve: a string indicating the name of the module.
2. options: an object indicating the options to pass to the module. These options vary for each module, and you should refer to the module’s documentation for details on them.
3. resources: a string indicating whether the module shares the dependency container with the Medusa core. Its value can either be shared or isolated. Refer to the Modules documentation for more details.
4. alias: a string indicating a unique alias to register the module under. Other modules can’t use the same alias.
5. main: a boolean value indicating whether this module is the main registered module. This is useful when an alias is used.

Example

medusa-config.js

module.exports = {
  modules: {
    eventBus: {
      resolve: "@medusajs/event-bus-local",
    },
    cacheService: {
      resolve: "@medusajs/cache-redis",
      options: { 
        redisUrl: process.env.CACHE_REDIS_URL,
        ttl: 30,
      },
    },
    // ...
  },
  // ...
}

featureFlags

Some features in the Medusa backend are guarded by a feature flag. This ensures constant shipping of new features while maintaining the engine’s stability.

You can specify whether a feature should or shouldn’t be used in your backend by enabling its feature flag. Feature flags can be enabled through either environment variables or through this configuration exported in medusa-config.js.

If you want to use the environment variables method, learn more about it in the Feature Flags documentation.

The featureFlags configuration is an object. Its properties are the names of the feature flags. Each property’s value is a boolean indicating whether the feature flag is enabled.

You can find available feature flags and their key name here.

Example

medusa-config.js

module.exports = {
  featureFlags: {
    product_categories: true,
    // ...
  },
  // ...
}

Note

After enabling a feature flag, make sure to run migrations as it may require making changes to the database.

Was this section helpful?

Prerequisites​

Environment Variables​

projectConfig​

store_cors​

Example​

admin_cors​

Example​

cookie_secret​

Example​

jwt_secret​

Example​

database_database​

Example​

database_url​

Example​

database_schema​

database_logging​

Example​

database_extra​

Example​

Properties​

redis_url​

Example​

redis_prefix​

Example​

redis_options​

Example​

session_options​

Example​

Properties​

http_compression​

Example​

Properties​

jobs_batch_size​

Example​

plugins​

Example​

modules​

Example​

featureFlags​

Example​

Prerequisites

Environment Variables

projectConfig

store_cors

Example

admin_cors

Example

cookie_secret

Example

jwt_secret

Example

database_database

Example

database_url

Example

database_schema

database_logging

Example

database_extra

Example

Properties

redis_url

Example

redis_prefix

Example

redis_options

Example

session_options

Example

Properties

http_compression

Example

Properties

jobs_batch_size

Example

plugins

Example

modules

Example

featureFlags

Example