jsonschema

jsonschema is an implementation of the JSON Schema specification for Python.

>>> from jsonschema 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:

$ jsonschema --instance sample.json sample.schema

Features

• Partial support for Draft 2020-12 and Draft 2019-09, except for dynamicRef / recursiveRef and $vocabulary (in-progress). Full support for Draft 7, Draft 6, Draft 4 and Draft 3
• Lazy validation that can iteratively report all validation errors.
• Programmatic querying of which properties or items failed validation.

Installation

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

$ pip install jsonschema

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 jsonschema's test suite on all of the versions of Python jsonschema supports. If you don't have all of the versions that jsonschema 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 jsonschema.tests package.

Benchmarks

jsonschema's benchmarks make use of pyperf. Running them can be done via:

$ tox -e perf

Community

The JSON Schema specification has a Slack, with an invite link on its home page. Many folks knowledgeable on authoring schemas can be found there.

Otherwise, asking questions on Stack Overflow is another means of getting help if you're stuck.

Contributing

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 Libera (nick: Julian) in various channels, including #python.

If you feel overwhelmingly grateful, you can also sponsor me.

And for companies who appreciate jsonschema and its continued support and growth, jsonschema is also now supportable via TideLift.