github.com/prebid/prebid-server@v0.275.0/docs/developers/configuration.md (about)

     1  # Configuration
     2  
     3  Configuration is handled by [Viper](https://github.com/spf13/viper), which supports [many ways](https://github.com/spf13/viper#why-viper) of setting config values.
     4  
     5  As a general rule, Prebid Server will log its resolved config values on startup and exit immediately if they're not valid.
     6  
     7  For development, it's easiest to define your config inside a `pbs.yaml` file in the project root.
     8  
     9  ## Available options
    10  
    11  For now, see [the contract classes](../../config/config.go) in the code.
    12  
    13  Also note that `Viper` will also read environment variables for config values. Prebid Server will look for the prefix `PBS_` on the environment variables, and map underscores (`_`)
    14  to periods. For example, to set `host_cookie.ttl_days` via an environment variable, set `PBS_HOST_COOKIE_TTL_DAYS` to the desired value.