An implementation of JSON Schema validation for Python, forked to avoid dependency issues

pip install jsonschemanlplab==



PyPI version Supported Python versions Travis build status AppVeyor build status ReadTheDocs status

This is a fork of https://github.com/Julian/jsonschema which exists only to circumvent dependency incompatibilities.

jsonschemanlplab is an implementation of JSON Schema for Python (supporting 2.7+ including Python 3).

>>> from jsonschemanlplab import validate

>>> # A sample schema, like what we'd get from json.load()
>>> schema = {
...     "type" : "object",
...     "properties" : {
...         "price" : {"type" : "number"},
...         "name" : {"type" : "string"},
...     },
... }

>>> # If no exception is raised by validate(), the instance is valid.
>>> validate(instance={"name" : "Eggs", "price" : 34.99}, schema=schema)

>>> validate(
...     instance={"name" : "Eggs", "price" : "Invalid"}, schema=schema,
... )                                   # doctest: +IGNORE_EXCEPTION_DETAIL
Traceback (most recent call last):
ValidationError: 'Invalid' is not of type 'number'

It can also be used from console:

$ jsonschemanlplab -i sample.json sample.schema



jsonschemanlplab is available on PyPI. You can install using pip:

$ pip install jsonschemanlplab

Release Notes

Version 3.0 brings support for Draft 7 (and 6). The interface for redefining types has also been majorly overhauled to support easier redefinition of the types a Validator will accept or allow.

jsonschemanlplab is also now tested under Windows via AppVeyor.

Thanks to all who contributed pull requests along the way.

Running the Test Suite

If you have tox installed (perhaps via pip install tox or your package manager), running tox in the directory of your source checkout will run jsonschemanlplab's test suite on all of the versions of Python jsonschemanlplab supports. If you don't have all of the versions that jsonschemanlplab is tested under, you'll likely want to run using tox's --skip-missing-interpreters option.

Of course you're also free to just run the tests on a single version with your favorite test runner. The tests live in the jsonschemanlplab.tests package.


jsonschemanlplab's benchmarks make use of perf.

Running them can be done via tox -e perf, or by invoking the perf commands externally (after ensuring that both it and jsonschemanlplab itself are installed):

$ python -m perf jsonschemanlplab/benchmarks/test_suite.py --hist --output results.json

To compare to a previous run, use:

$ python -m perf compare_to --table reference.json results.json

See the perf documentation for more details.


There's a mailing list for this implementation on Google Groups.

Please join, and feel free to send questions there.


I'm Julian Berman.

jsonschema is on GitHub.

Get in touch, via GitHub or otherwise, if you've got something to contribute, it'd be most welcome!

You can also generally find me on Freenode (nick: tos9) in various channels, including #python.

If you feel overwhelmingly grateful, you can woo me with beer money via Google Pay with the email in my GitHub profile.