"Plek" is Afrikaans. It means "Location". Plek is used to generate the correct base URLs for internal GOV.UK services, eg:

# on a dev machine
> Plek.find('frontend')
=> ""
# on a production machine
> Plek.find('frontend')
=> ""

This means we can use this in our code and let our environment configuration figure out the correct hosts for us at runtime.

In an environment where we have internal hostnames and external ones an option of external can be provided to determine whether an internal or external host is returned.

> Plek.find('frontend')
=> ""
> Plek.find('frontend', external: true)
=> ""

Technical documentation

See the API docs for full details of the API.

Running the test suite

bundle exec rake

Environment variables

For base URLs

The base URL Plek uses for each service can be set using environment variables.

Plek will use any variables set matching this pattern:

PLEK_SERVICE_ + the service name, uppercased with any hyphens converted to underscores + _URI.

For example, the variable for static would be PLEK_SERVICE_STATIC_URI.


To domain is based on the environment, and defaults to ''. The environment can be set using either RAILS_ENV or RACK_ENV.

You can prepend strings to the hostnames generated using: PLEK_HOSTNAME_PREFIX.

If PLEK_HOSTNAME_PREFIX is present, it will be prepended to the hostname unless the hostname appears in the comma-separated list PLEK_UNPREFIXABLE_HOSTS.

Override the asset URL with: GOVUK_ASSET_ROOT. The default is to generate a URL for the static service.

Override the website root with GOVUK_WEBSITE_ROOT. The default is to generate a URL for the www service.

If PLEK_USE_HTTP_FOR_SINGLE_LABEL_DOMAINS=1 (or anything beginning with t or y), Plek will use http as the URL scheme instead of https for single-label domains. Single-label domains are domains with just a single name component, for example frontend or content-store, as opposed to or


MIT License

Versioning policy

This is versioned according to Semantic Versioning 2.0