Skip to content
A Python Object-Document-Mapper for working with MongoDB
Latest commit 0a431ea May 5, 2016 @thedrow thedrow Merge pull request #1289 from closeio/fix-typo
Fix typo in the docstring for __len__



Info:MongoEngine is an ORM-like layer on top of PyMongo.
Author: Harry Marr (
Maintainer:Ross Lawley ( Code Health


MongoEngine is a Python Object-Document Mapper for working with MongoDB. Documentation available at - there is currently a tutorial, a user guide and an API reference.


We recommend the use of virtualenv and of pip. You can then use pip install -U mongoengine. You may also have setuptools and thus you can use easy_install -U mongoengine. Otherwise, you can download the source from GitHub and run python install.


  • pymongo>=2.7.1
  • sphinx (optional - for documentation generation)

Optional Dependencies

  • Image Fields: Pillow>=2.0.0
  • dateutil>=2.1.0


Some simple examples of what MongoEngine code looks like:

class BlogPost(Document):
    title = StringField(required=True, max_length=200)
    posted = DateTimeField(
    tags = ListField(StringField(max_length=50))

class TextPost(BlogPost):
    content = StringField(required=True)

class LinkPost(BlogPost):
    url = StringField(required=True)

# Create a text-based post
>>> post1 = TextPost(title='Using MongoEngine', content='See the tutorial')
>>> post1.tags = ['mongodb', 'mongoengine']

# Create a link-based post
>>> post2 = LinkPost(title='MongoEngine Docs', url='')
>>> post2.tags = ['mongoengine', 'documentation']

# Iterate over all posts using the BlogPost superclass
>>> for post in BlogPost.objects:
...     print '===', post.title, '==='
...     if isinstance(post, TextPost):
...         print post.content
...     elif isinstance(post, LinkPost):
...         print 'Link:', post.url
...     print

>>> len(BlogPost.objects)
>>> len(TextPost.objects)
>>> len(LinkPost.objects)

# Find tagged posts
>>> len(BlogPost.objects(tags='mongoengine'))
>>> len(BlogPost.objects(tags='mongodb'))


To run the test suite, ensure you are running a local instance of MongoDB on the standard port, and run: python nosetests.

To run the test suite on every supported Python version and every supported PyMongo version, you can use tox. tox and each supported Python version should be installed in your environment:

# Install tox
$ pip install tox
# Run the test suites
$ tox

If you wish to run one single or selected tests, use the nosetest convention. It will find the folder, eventually the file, go to the TestClass specified after the colon and eventually right to the single test. Also use the -s argument if you want to print out whatever or access pdb while testing.

$ python nosetests --tests tests/fields/ -s



We welcome contributions! see the Contribution guidelines

Something went wrong with that request. Please try again.