zigbee2mqtt is a nice little piece of software that allows you to connect zigbee devices without the need of proprietary gateways. It’s based on zigbee-shpeherd and it runs on nodejs. You can read more on the forums or directly in the documentation
The addon is still having very short release cycles because of fast pace development of zigbee2mqtt but it’s stable enough for usage. Have a look at the extensive documentation and if you need extra support use the issue tracker.