Format is rather experimental right now and has some issues especially around formatting floats. Maybe I should finally get into it an finish it, now that Jason is mostly done

One way is with Michał Muskała’s Format library GitHub - michalmuskala/format: A simple string formatter for Elixir · GitHub. I’m not sure if there’s any documentation, but you can do:

def print_url(id, language, url) do
  url
  |> Format.compile()
  |> Format.string(id: id, language: language)
  |> IO.puts()
end

where url is a string that contains {id} and {language}, which get replaced by the corresponding values specified in Format.string.

My personal syntactic preference would be

...
  |> Format.string([id: id, language: language])
...

I suggest you to use :io_lib.format(format, [arg1, ...]) |> to_string(). See the documentation of :io_lib.format.

It is one less dependency if you use this function because it is in the standard library.