psl 2025.5.26

Mozilla Public Suffix list as a Python package and updated daily

psl

Mozilla Public Suffix list as a Python package and updated daily.

Install via python -m pip install psl

See https://publicsuffix.org for more information regarding the list itself.

API

The package provides the following members as an API:

domain_suffixes()

def domain_suffixes(dn: str, *, icann_only: bool=False) -> Suffixes: ...

Queries the Public Suffix list for the given domain and returns a named tuple containing the public and private suffixes for the domain. Either value can be None if that field isn't available. (eg private=None for the domain com)

domain_can_set_cookie()

def domain_can_set_cookie(*, http_domain: str, cookie_domain: str) -> bool: ...

Determines if a user-agent that receives an HTTP response from domain <http_domain> with Set-Cookie headers with parameter Domain=<cookie_domain> should allow that cookie to be set. This disallows cookies from being set on public suffixes and on domains that the HTTP domain has no authority over.

This is the same mechanism that modern browsers use to determine whether it's safe to set a cookie to prevent 'super-cookies'.

License

MPL-2.0