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.


The NodeJS buildpack detects if your build is Node by looking for a package.json file. If found, the build will execute the following NPM (or Yarn) commands.

If no Procfile is found, a web process will be started with npm start .

You can customize the node version using the engines field of your package.json. For example


The Python buildpack detects if your build is Python by looking for a requirements.txt file. If found, dependencies will be installed using pip.

The default Python version is 3.6.

You can customize the Python version by adding a runtime.txt file to the root of your project. The contents of the file should include the version. For example,


The Go buildpack will detect your build is Go if you are using go modules, dep, govendor, glide, GB, or Godep. If detected, dependencies will be installed and the source compiled.

If no Procfile is found, a web process will be started with go run main.go.


The Ruby buildpack detects if your build is Ruby by looking for Gemfile and Gemfile.lock files. If found, dependencies will be installed with bundle install.


The Java buildpack detects if your build is Java by looking for a pom.xml file. If found, Maven will download all dependencies and build the project.


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, all process will be started by running their respective command.

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.


We will look for and use a Dockerfile at the project root if it exists.

If you need to use the environment variables that Railway injects at build time, you must specify them in the Dockerfile with

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