Laravel notification client selection

Requirements: 1. the company's HRMS needs to push notifications, but for various reasons, the server cannot be exposed to the public network! 2. it is best to be free and the ecosystem is better (other microservices can be integrated in the future) 3. there are multi-platform clients because of the first one, so the public account cannot be implemented! I have read... the requirements are as follows:
1. the company's HRMS needs to push notifications, but for various reasons, the server cannot be exposed to the public network!
2. it is best to be free and the ecosystem is better (other microservices can be integrated in the future)
3. multi-platform clients

The public account cannot be implemented because of the first one!

After reading the BearyChat Incoming robot, it seems that it can only be pushed to discussion groups and not to individuals!
But other ecosystems are doing very well, so I want to know if there is a similar platform!

Reply content:

The requirements are as follows:
1. the company's HRMS needs to push notifications, but for various reasons, the server cannot be exposed to the public network!
2. it is best to be free and the ecosystem is better (other microservices can be integrated in the future)
3. multi-platform clients

The public account cannot be implemented because of the first one!

After reading the BearyChat Incoming robot, it seems that it can only be pushed to discussion groups and not to individuals!
But other ecosystems are doing very well, so I want to know if there is a similar platform!