Backstage ships with a flexible configuration system that provides a simple way to configure Backstage apps and plugins for both local development and production deployments. It helps get you up and running fast while adapting Backstage for your specific environment. It also serves as a tool for plugin authors to use to make it simple to pick up and install a plugin, while still allowing for customization.
Configuration is stored in YAML files where the defaults are
app-config.local.yaml for local overrides. Other sets of files can by
loaded by passing
--config <path> flags. The configuration files themselves
contain plain YAML, but with support for loading in secrets from various sources
using for example
It is also possible to supply configuration through environment variables, for
APP_CONFIG_app_baseUrl=https://staging.example.com. However these
should be used sparingly, usually just for temporary overrides during
development or small tweaks to be able to reuse deployment artifacts in
The configuration is shared between the frontend and backend, meaning that
values that are common between the two only need to be defined once. Such as the
For more details, see Writing Configuration.
The configuration is validated using JSON Schema definitions. Each plugin and
package can provide pieces of the configuration schema, which are stitched
together to form a complete schema during validation. The configuration schema
is also used to select what configuration is available in the frontend using a
visibility keyword, as configuration is by default only available in
You can validate your configuration against the schema using
backstage-cli config:check, and define a schema for your own plugin either
using JSON Schema or TypeScript. For more information, see
As a plugin developer, you likely end up wanting to define configuration that you want users of your plugin to supply, as well as reading that configuration in frontend and backend plugins. For more details, see Reading Configuration and Defining Configuration.
More details are provided in dedicated sections of the documentation.