How to close a mongodb python connection?

The safest way to close a pymongo connection would be to use it with 'with':

with pymongo.MongoClient(db_config['HOST']) as client:
    db = client[ db_config['NAME']]
    item = db["document"].find_one({'id':1})
    print(item)

Use close() method on your MongoClient instance:

client = pymongo.MongoClient()

# some code here

client.close()

Cleanup client resources and disconnect from MongoDB.

End all server sessions created by this client by sending one or more endSessions commands.

Close all sockets in the connection pools and stop the monitor threads.