The connection pooling is handled by the underlying Pymongo driver, though you can explicitly set it, it should be on by default. (See Configuring Connections: https://humbledb.readthedocs.io/en/latest/tutorial.html#configuring-connections)

I realize this is a 9 year old question without answers, but I recently updated the humbledb dependencies to be compatible with the latest Pymongo driver software so I’m leaving this here in case someone needs an answer.