This library is useful to provide an API for C++ libraries dealing with a problem domain with its own notation. Interfaces built with Metaparse make it possible for the users of the interface to use the domain's own notation, which makes it easier to write and maintain the code. Users of the interface don't need to learn a new notation (trying to follow the problem domain's original one) library authors constrained by the C++ syntax can provide. Example problem domains are regular expressions and SQL queries.

Metaparse can also be useful to build libraries validating the content of string literals at compile time instead of doing it at runtime or not doing it at all. This can help finding (and fixing) bugs in the code early (during compilation). An example problem domain is printf.