Set the NODE_VERSION environment variable, or add a .node-version file to your project root containing only the version number:

For additional options, see Setting Your Node.js Version.

Set the BUN_VERSION environment variable:

Set the PYTHON_VERSION environment variable, or add a .python-version file to your project root containing only the version number:

For details, see Setting Your Python Version.

You can also set versions for the following package management tools:

• uv
• Poetry

Set the ruby directive in your Gemfile, or add a .ruby-version file to your project root containing only the version number:

For details, see Setting Your Ruby Version.

Render's native Go environment automatically updates to the latest stable Go 1.x version, usually within 24 hours of a new release. After an update, your service starts using the new version with its next deploy.

You can't pin to a specific Go version unless you deploy a Docker image.

Set the RUSTUP_TOOLCHAIN environment variable, or add a rust-toolchain file to your project root containing only the toolchain version:

For details, see Specifying a Rust Toolchain.

Set the ELIXIR_VERSION and/or ERLANG_VERSION environment variables.

If you don't set ERLANG_VERSION, Render automatically uses an Erlang version that's compatible with your ELIXIR_VERSION.

For details, see Setting Your Elixir and Erlang Versions.

To use any language besides those listed above, deploy your code as a Docker image.