So far the closest thing I've been able to find is warlock, which advertises this workflow:

Build your schema

>>> schema = {
    'name': 'Country',
    'properties': {
        'name': {'type': 'string'},
        'abbreviation': {'type': 'string'},
    },
    'additionalProperties': False,
}

Create a model

>>> import warlock
>>> Country = warlock.model_factory(schema)

Create an object using your model

>>> sweden = Country(name='Sweden', abbreviation='SE')

However, it's not quite that easy. The objects that Warlock produces lack much in the way of introspectible goodies. And if it supports nested dicts at initialization, I was unable to figure out how to make them work.

To give a little background, the problem that I was working on was how to take Chrome's JSONSchema API and produce a tree of request generators and response handlers. Warlock doesn't seem too far off the mark, the only downside is that meta-classes in Python can't really be turned into 'code'.

Other useful modules to look for:

• jsonschema - (which Warlock is built on top of)
• valideer - similar to jsonschema but with a worse name.
• bunch - An interesting structure builder thats half-way between a dotdict and construct

If you end up finding a good one-stop solution for this please follow up your question - I'd love to find one. I poured through github, pypi, googlecode, sourceforge, etc.. And just couldn't find anything really sexy.

For lack of any pre-made solutions, I'll probably cobble together something with Warlock myself. So if I beat you to it, I'll update my answer. :p

Summarising the other answers, here are the JSON schema generators proposed so far:

Online:

• https://www.liquid-technologies.com/online-json-to-schema-converter (1 input)
• http://www.jsonschema.net (1 input)
• https://easy-json-schema.github.io (1 input)
• https://json.ophir.dev/ (1 input, nice UI)

Python:

• https://github.com/gonvaled/jskemator (1 input but allows iteration)
• https://github.com/perenecabuto/json_schema_generator (1 input)
• https://github.com/rnd0101/json_schema_inferencer (1 input I think)
• https://pypi.python.org/pypi/genson/ (multiple inputs)
• https://pypi.python.org/pypi/skinfer (multiple inputs)

NodeJS:

• https://github.com/Nijikokun/generate-schema (multiple inputs (pass object array))
• https://github.com/easy-json-schema/easy-json-schema (1 input)
• https://github.com/aspecto-io/genson-js (multiple inputs)

Ruby:

• https://github.com/maxlinc/json-schema-generator (1 input)

A library that does exactly this is hypothesis-jsonschema

Hypothesis is a library that can generate arbitrary data that conforms to a given specification.

hypothesis-jsonschema makes it possible to convert JSON Schema into specifications that can be used by Hypothesis.

Here is an example showing a unit test written using Hypothesis and hypothesis-jsonschema:

from hypothesis import given

from hypothesis_jsonschema import from_schema


@given(from_schema({"type": "integer", "minimum": 1, "exclusiveMaximum": 10}))
def test_integers(value):
    assert isinstance(value, int)
    assert 1 <= value < 10