HTTP::Throwable provides a set of strongly-typed, PSGI-friendly exception implementations corresponding to the HTTP error status code (4xx-5xx) as well as the redirection codes (3xx). This particular package (HTTP::Throwable) is the shared role for all the exceptions involved. It's not intended that you use HTTP::Throwable directly, although you can, and instructions for using it correctly are given below. Instead, you probably want to use HTTP::Throwable::Factory, which will assemble exception classes from roles needed to build an exception for your use case. WWW: https://metacpan.org/release/HTTP-Throwable