Placeables

Text in Fluent may use special syntax to incorporate small pieces of programmable interface. Those pieces are denoted with curly braces { and } and are called placeables.

It's common to use placeables to interpolate external variables into the translation. Variable values are provided by the developer and they will be set on runtime. They may also dynamically change as the user uses the localized product.

# $title (String) - The title of the bookmark to remove.
remove-bookmark = Really remove { $title }?

It's also possible to interpolate other messages and terms inside of text values.

-brand-name = Firefox
installing = Installing { -brand-name }.

Lastly, placeables can be used to insert special characters into text values. For instance, due to placeables using { and } as delimiters, inserting a literal curly brace into the translation requires special care. Quoted text can be effectively used for the purpose:

opening-brace = This message features an opening curly brace: {"{"}.
closing-brace = This message features a closing curly brace: {"}"}.