Interfaces for Python

Interfaces are objects that specify (document) the external behavior of objects that 'provide' them. An interface specifies behavior through informal documentation, attribute definitions, and invariants. `zope.interface` provides an implementation of 'object interfaces' for Python, facilitating Design By Contract. It is currently at version 8.2 (as of January 9, 2026) and is actively maintained by the Zope Toolkit project.