The Railway MongoDB database service allows you to provision and connect to a MongoDB database with zero configuration.


You can add a MongoDB database via the CMD + K menu or by clicking the + New button on the Project Canvas.

GIF of the Adding Database


There are two ways to connect to a MongoDB database:

When you deploy your MongoDB database, you will have access to two environment variables that enable one of the two connection types (private or public).

As you create more services in your project, you can use Reference Variables to easily connect to the MongoDB database.

Private Networking

To access your MongoDB database from another service within the same project, you can use the connection string stored in the MONGO_PRIVATE_URL environment variable.

This connection string uses Private Networking to route communication to your service over the private network.

TCP Proxy Connection

To access your MongoDB database over the public internet, you can use the connection string stored in the DATABASE_URL environment variable available in the service.

This connection string uses the TCP Proxy connection to route communication to your service over the public internet.

You can also connect using mongo shell:


The following variables are included in the MongoDB service and can be referenced in other services:


Connect to your MongoDB container using your library of choice and supplying the appropriate environment variables.


The MongoDB database service uses the mongo:latest docker image.

Custom Start Command

The MongoDB database service starts with the following Start Command to enable communication over Private Network: mongod --ipv6 --bind_ip ::,

Changing System Variables

Tailor your MongoDB service to your needs by adding any variables relevant to the mongo:latest image.

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