Welcome to Cerberus

Cerberus is a lightweight and extensible data validation library for Python.

CERBERUS, n. The watch-dog of Hades, whose duty it was to guard the entrance; everybody, sooner or later, had to go there, and nobody wanted to carry off the entrance. - Ambrose Bierce, The Devil’s Dictionary

Cerberus provides type checking and other base functionality out of the box and is designed to be easily extensible, allowing for easy custom validation. It has no dependencies and is thoroughly tested under Python 2.6, Python 2.7, Python 3.3, Python 3.4, PyPy and PyPy3.

At a Glance

You define a validation schema and pass it to an instance of the Validator class:

>>> schema = {'name': {'type': 'string'}}
>>> v = Validator(schema)

Then you simply invoke the validate() to validate a dictionary against the schema. If validation succeeds, True is returned:

>>> document = {'name': 'john doe'}
>>> v.validate(document)
True