Hang on @Gigitsu I have you covered with my own contribution to Phoenix xD.

Check out the :reloadable_apps option that I added to Phoenix a while ago. My use case was similar but not identical, so I am wondering if it will work for you.

config :your_app, Backoffice.Endpoint,
  reloadable_apps: [:frontend_1, :frontend_2, :backoffice, :core, :common]

Thanks @samaravilha.

I’ve managed to get code reload working by adding the following configurations in my dev.exs file

config :phoenix_live_reload, :dirs, [
  Path.expand("../apps/my_app", __DIR__),
  Path.expand("../apps/common", __DIR__),
  Path.expand("../apps/core", __DIR__)
]

config :my_app, MyApp.Endpoint,
  live_reload: [
    patterns: [
      ~r"../common/lib/common/(\w+/)*.*(ex|heex)$",
      ~r"../core/lib/core/(\w+/)*.*(ex|heex)$",
      ~r"priv/gettext/.*(po)$",
      ~r"priv/static/.*(js|css|png|jpeg|jpg|gif|svg)$",
      ~r"lib/my_app/(controllers|live|components)/.*(ex|heex)$"
    ]
  ]

config :my_app, MyApp.Endpoint,
  ...
  reloadable_apps: [:my_app , :core, :common],
  ...