Simple blog REST API with Eve http://python-eve.org/. Install Mongo and Eve and you're good to go!

blog-backend-api.py

"""
1. Install Mongo
2. pip install eve
3. python blog-backend-api.py
"""

# Mongo setup
MONGO_PORT = 27017
MONGO_USERNAME = 'test-blog'
MONGO_PASSWORD = 'test-blog'
MONGO_DBNAME = 'test-blog'

SERVER_NAME = '127.0.0.1:5000'

# Enable reads (GET), inserts (POST) and DELETE for resources/collections
# (if you omit this line, the API will default to ['GET'] and provide
# read-only access to the endpoint).
RESOURCE_METHODS = ['GET', 'POST']

# Enable reads (GET), edits (PATCH) and deletes of individual items
# (defaults to read-only item access).
ITEM_METHODS = ['GET', 'PATCH', 'DELETE']

# We enable standard client cache directives for all resources exposed by the
# API. We can always override these global settings later.
CACHE_CONTROL = 'max-age=20'
CACHE_EXPIRES = 20

# Define blog data structure
# Schema definition, based on Cerberus grammar. Check the Cerberus project
# (https://github.com/nicolaiarocci/cerberus) for details.

users = {
    'schema': {
        'name': {
            'type': 'string',
            'minlength': 1,
            'maxlength': 50,
        },
        
        'username': {
            'type': 'string',
            'minlength': 1,
            'maxlength': 20,
            'unique': True
        }
    }
}

blog_posts = {
    'schema': {
        'title': {
            'type': 'string',
            'minlength': 1,
            'maxlength': 50,
        },
        
        'text': {
            'type': 'string'
        },

        'author': {
            'type': 'objectid',
            'data_relation': {
                 'resource': 'users'
             }
        }
    }
}


comments = {
    'schema': {
        'text': {
            'type': 'string',
            'minlength': 1,
            'maxlength': 140,
        },

        'author': {
            'type': 'objectid',
            'data_relation': {
                 'resource': 'users'
            }
        },

        'target_post': {
            'type': 'objectid',
            'data_relation': {
                 'resource': 'blog_posts'
            }
        }
    }
}

# The DOMAIN dict explains which resources will be available and how they will
# be accessible to the API consumer.
DOMAIN = {
    'users': users,
    'blog_posts': blog_posts,
    'comments': comments
}