Builds

Railway uses Cloudnative Buildpacks to attempt to build and deploy with zero configuration. Currently, we support the following languages out of the box

• NodeJS
• Python
• Go
• Ruby
• Java

If you have a language that you want us to support, please don't hesitate to reach out and let us know.

Procfile

Railway supports Procfiles, a file that can be included in the project to specify which command to run when the deployment starts.

A Procfile is in the format of

When Railway deploys your build, the process listed in the file will be started by running the respective command. Note: Railway can only execute one process per Procfile.

Note: some buildpacks specify a default start command

Web process

HTTP servers should use the web process type. This process should listen on the PORT environment variable and will receive HTTP traffic. For example,

Custom Buildpacks

By default, the appropriate buildpacks are selected by inspecting the source files of a project. For more control, a project.toml file can be used to achieve a more custom setup.

Here is an example project.toml file that forces a NodeJS project to use Yarn instead of NPM.

Experimental Builder

By default Railway will attempt to build your app with the heroku/buildpacks:18 builder, which is based on how Heroku builds apps. We are experimenting using a custom builder that will allow us to have more control and flexibility in how your source code gets built and deployed on the platform. The new builder has support for

• NodeJS
• Go
• PHP
• Ruby
• Java
• .NET
• Nginx
• Python

You can opt-in to using this new builder by enabling it in your projects deployment settings.

Please note that this is still in development and may not be 100% backwards compatible with the previous builder. If you have any thoughts/concerns/questions/feedback, we would love to hear from you!