how to make new campaign(firebase messaging) through REST API

[HYEYOUNG HALEY JI]

hi

i am building an app which is basically web app.

this project is set with java + spring boot + maven 

and launched in android app on google play store , ios app on app store.

so my question is

how to i send push notification through my admin web site ( web ux/ui) 

to all of my users by android app and ios app.

currently i am focusing on sending a message using this

'https://fcm.googleapis.com/v1/projects/project-id/messages:send'

to basically save my push data to cloud messaing campaigns section.

is this even possible? 

thanks in advance.